I think everybody deals with some of these feelings from time to time, but - for me - it comes down to simply choosing not to indulge in regret. It's a wasted emotion to me, as it does nothing to make anything better, and there's nothing I can do about what's in the past. Somewhere, somehow, over the years, I've adopted something of a stoic mindset (even before I knew what stoicism was) and my outlook is just kinda rooted in that.

I also, for whatever reason, am much higher in terms of self-efficacy than self-esteem, and my self-efficacy is such that I pretty much always believe that tomorrow can be better than today, because I see no reason to believe there is any limit to what I can still accomplish.

That said, it gets tougher sometimes. I'll turn 40 this year, and I was just diagnosed with diabetes a few months ago, and my doctor is now investigating the possibility that I may have something called Cushing's Syndrome. Uuugh, ya know?

But when I start feeling deflated, I usually just put some metal on and jam out... Here, try this:

http://www.youtube.com/watch?v=354MU3l-25M

http://www.youtube.com/watch?v=mMorZnGxhv4

http://www.youtube.com/watch?v=i3MXiTeH_Pg

I also keep reminding myself of that scene near the end of Matrix:Revolutions where Agent Smith is asking Neo "Why, Mr. Anderson, why do you keep getting back up? You know you can't win. Why, Mr. Anderson"? and Neo is like "Because. I. Choose. To." Sends chills down my spine even now and reminds me that we get to choose (for the sake of argument, let's say I believe in free will). So I can't control what happened in the past, but I can damn sure choose to influence what happens in the future.

I am objectively in a place I am not happy with, but am convinced things cannot get any better. You may say that I'm not speaking rationally, but reality can validate every one of my worries and regrets. I don't think I am exaggerating or fabricating anything, rather I am reflecting on what has happened and observing patterns, or so I think I am.

Do any of you have any experience with this?

Yeah, it's called depression. Somebody below mentioned CBT (Cognitive Behavioral Therapy), and from what I've seen/heard, I second the motion to find a pro to talk to about that. But in the short term, you can try some basic CBT like stuff on yourself. Check your inner dialog and when you find negative thoughts in you mind like "Things can NOT get any better", stop and ask yourself "is that really, really, absolutely true?" Force yourself to look for an "existence proof" of even ONE small counter-example that disproves the thesis that "things can NOT get any better." Once you find that counter-example (and I'm pretty sure you can) then you have to force your inner dialog along the lines of "OK, now I see that it's not true that things can't get any better. So what other ways CAN things get better?" and "what steps can I take to move things towards a better state?", etc.

You can also try going meta and ask yourself "OK, I just thought this really negative thought. Why? What prompted me to think that? And is whatever it was really that significant? Can I just stop thinking about $WHATEVER?" etc. It's amazing how much you can change your mood and emotions by just consciously thinking about your inner dialog.

Anyway, I'm not expert or professional, so by all means, seek professional help if you find the negativity persisting and if it's affecting your day to day life in a bad way.