Hey I am 25 live in the Uk for some context however relevant right I think I know exactly what your feeling and I hope the answer I share lifts all anxiety and ushers in peace.First off congratulations on finishing I can imagine it was tough to complete but you did it! Secondly forgive me for any punctuation or grammar mistakes I'm writing this from an iPhone as it's late here laptops off and I'm reading hacker news before bed.

So you've played the game of life and at the end when we all believed education lead to success we realise we have been bamboozled. The "feeling lost" is because of this, you felt somewhere on a subconscious level that if you achieved this thing then it would secure you potentially financially or more so directionally as in it would lead you to the next step.What is evident is that it hasn't and the reason why or part of the reason is that we have not taken the time to truly get in touch with our true self the self that wanted to be a artist but through social pressures or the need to conform like a pre commenter put we have ignored that sentiwnt skill shouting within saying our true desires until it became a whisper and then a faint cry.This was reinforced by the fact that in school we know in X months time we will receive a result dictating our progression to the next level or path this gets repeated a fair number of times if you add up each exam each year up until college (your equivalent to university) so we develop a carrot and stick approach believing that the next thing will be better / progression and thus drawing is closer to this ever elusive victory. It's a lie the wizard is just a man being a curtain.In deadling with the going back to school premise you mentioned I wouldn't if the reason was based on fear I.e scared of not wanting to be a jobless person and so we go to what we have known all our life that being education.If after months of mulling you honestly thought that this would allow you to feel fulfilled and was your calling then by all means go back to school.

Being more than a 9-5
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Being more than a 9-5 that emotion your feeling is your inner self the one you quieted earlier in your life (for those that jumped to here please read prior to this it's mentioned above ) that knows what you want and has always known.You are more but you've played a game which teaches you to compete,quiet this type of self reflection and expressiveness ,not be creative and not to go against the system which churns out people that are meant to think a certain way.
Your emotions are powerful they are actually indicators to whether your flowing with life or against it ,the true nature of humans is joy when I code or solve a problem or workout or write an observation I feel joy I don't feel resistance.The resistance your feeling is your inner senses telling you that something is not right we are not flowing.

So what are you trying to tell me?That I can dodge bullets?
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Lol excuse the title I know when I get on a prose like this it can come across stoic and impractical so I just took the matrix quote as neo was feeling the same thing when answering Morpheus.

What I would do or better yet what I have done ...the first year of uni I felt the same thing lost and I was just staring at my impending doom.So what I did is this:
-Be grateful you finished a huge degree and maybe through your humility (which I respect)you didn't mention the joy or thankfulness of completing that .When your constantly grateful you rarely feel jealously or hate as your just grateful with being/existing.

-Don't give this a heavy weighting.This is just a situation no different than breaking a nail because it involves your life you may feel overwhelmed and therefore make rash decisions so treat this as anything else a momentary situation that has a solution that will come to you as the observation of something missing is the first step to finding it.

-Get honest with yourself what are you about do you like business or did you just do it as the prospectus of a reputable company sounded good? it sounds like your a very social person who wears their heart on their sleeve so maybe there's a talent you can leverage.Whatever it is find it.

-Take some time out anytime you feel lost its just a sign that we may be off track from our inner compass so maybe 2 weeks away if not possible then maybe a weekend away with just yourself.The reason I stress just you is because you need to get in tune with yourself which is achievable in quiet space so that you can hear that inner murmur of what you want to do turn into a roar.Note this isn't running away from the problem the problem exists within you,your going away to break the habitual ways of your life which have potentially got you into this chasing the elusive carrot activity.

-Remove the ego now there's people who are lawyers my because it was their God given talent but because it "paid well" this is ridiculous understand the need for pecuniary stability but for me to do something that's not aligned with what I believe to be my calling is not only fake but ridden with stress and unfulfillment and you can see that with 1 in 5 multi million dollar CEOs being depressed.So kick the ego if your inner self says you should be a dog walker then be a dog walker walk dogs with grace and poise and I guarantee you won't feel judgement or even care for what people say as you will be fulfilled you have a business degree so maybe you can make a business out of
It why not .Taking a pause from social media may help you during this phase as social media flashes information that not only can trigger you to keep up with the Jones' but also harbours a competitive mindset which will have you doing things you don't want to do just to appear a certain way to your peers.

-meditate for 15 minutes twice a day the reason for this is that you need to still that mind I can imagine right now it's busy telling you all sorts of lies like people think I'm a failure in lost ,I wasted my life all these are lies and it's just the self which has always had a carrot at the end of the year waking up to find that there's no carrot coming this time as education is over.In stilling the mind your able to gain connection back to the inner self which is the true self.

-exercise more or start this is just the ying and yang ,night and day to meditation tiny Robbins says fear which you may feel is a physically thing so get the body fit as well as the mind.

Finally I would urge you to consider this most time we feel lost or stressed or self defeating its because we have attached our self to a thing ... Take this, you eat a banana but you would never say you are a banana as that is ridiculous,but look at this you meet people and the first thing they say is I'm insert your job here and Pause for admiration.You are not your current situation the fact that you feel lost only once finishing your degree is potentially down to the fact that during your degree you was a student you associated with being a business student and it gave you a blanket and some direction till all you was ,was a student .Now your not a student you have lost that and hence feel lost but the truth was you wasn't a student that was just what you were doing it wasn't the entire being that is you.

I am not saying be nothing and go the Himalayas and meditate for 15 years.Have goals it's fine my goal is to grow spiritually physically and
Mentally in all ways possible I'm no fool we live in the weatern world so some goals cater to the ways of this society but above all I have spiritual goals to ensure whatever I attain I feel fulfilled and counter intuitively can live without as just being gives me joy.Start tuning into your self and as you pay attention to your self through )taking care of the self through the methods above )then the self will communicate more clearly with you and I know for sure the path will be clear.