1. Talk to more people about how you're feeling. Posting here was a good idea. You'll generally find support here. But talk to your parents about this. Talk to other adults. If you have a therapist or similar counsellor available to you, talk to them about it (you don't have to have "a problem" to have a therapist btw). Absolutely do not pen this up inside of you or it will eat you, making your fears more likely to become real.

2. Let go. You are ultimately not in control of what happens for you (not "to" you). You only have control over your beliefs, thoughts, and behaviors. If it doesn't work out, but you worked really hard, what do you have to be guilty about? Also, do not let your career success be your self worth. Your parents love you and so do other people. That won't change (for the vast majority of people) if you disappoint them.

3. Don't give up if something doesn't go the way you want it to. This is where failure really happens. Listen, it took me way more years than it was supposed to, to finish college. It sounds like your father also understands this kind of thing. If something doesn't go how you want, take a deep breath, focus on the things that make you happy, and then go back and try again. Maybe try something different, or try the same thing in a different way. But try again. Real life success does not come from an unbroken series of victories. I read that when NASA selects astronauts, one of the things they look for is a history of difficulties and failures that were later overcome. While I was looking this up, I found many stories of astronauts that were rejected from NASA dozens of times before they finally made it into the program.

4. Don't work all the time. Your days, weeks, and quarters should look like starting from a place of rest, ratcheting up your energy levels and work outputs, then ratcheting down back to a place of rest. Have fun. Spend time with friends. Play (do things with no career value just for pleasure). Relax. Watch TV. When you have to work many hours in a row, know when enough is enough and just stop.

5. Related to this, care for yourself physically. Get regular exercise. Take care of your hygiene. Take care of your appearance. Relax as completely as you can. Make sure you're sleeping the right number of hours and with good quality (there are many things you can do to improve your sleep quality. Google this.) For me personally, a lot of this stuff feels like work. But when I get into good habits, it starts to feel instead like I'm truly living.

6. Adopt self-love. This manifests in your beliefs about yourself. Really, your question "How do I ensure that I do everything I possibly can...?" is about not believing in yourself. Believe in yourself. Tell yourself how much you believe in yourself. Advocate for yourself and what you need. You are a very complex being with many unconscious processes that are very interesting to learn about. Your needs do not always show themselves in obvious ways. So pay attention to what your body, emotions, and mind are telling you (without believing every silly thing your mind says), as if you were your own child that you are caring for. One thing that helps here is to listen to wise teachers who speak with kindness and universal love. I like Thic Nhat Hanh's lessons.

7. When you have started to do all of the above, your body and mind will function with greater rigor and clarity, from a place of peace and health. From here you will be more prepared to attain your goals. Now apply the basic strategies of study and work. Be efficient with your reading by first scanning, then skimming and finally reading. Space out your studies instead of cramming. You need to understand how your mind retains information, by gradually layering details onto a tree-like structure of knowledge and understanding. Work problems with your hands, on paper. Teach other people. Use mnemonics. All of these skills can be learned and will accelerate your success.