Growing up is growing pains. Hurts, but it's necessary to go through. When I first started working, the transition was hard, but I learnt a lot. Here are 3 lessons I found the most invaluable till now.
1) Setting expectations too high. It's true that in order to shine we have to give a 100%, but often times, when we were still young and energetic, we overestimated our measure of 100%. It is usually our 120-150%. Giving this overpowering 100% everyday is not sustainable - eventually you'll reach a burnout point. Reduce what you thought is 100%, not so much, but enough for you to do your job well, make your supervisor happy, and sustain for a much longer period of time.
2) Smile. An often underestimated value in the workplace. Everybody loves people who always smile to them, acknowledging their presence instead of ignoring them. You don't necessarily have to greet them cheerily and ask them sincerely how are they doing (although this is a super good time to practice the art of listening here too as they might actually tell you something they wouldn't otherwise!). Again, do not overdo it. There are days where you'd find office unbearable, and at these times you'd be unable to mask these if you overdo your smiles every day.
3) The fiercest people at your work, or the people that randomly criticize you (not always your peers or supervisors) in a bad way, may not necessarily hate you. Do not take this personally. More often than not, these people, no matter how small, realize that you have a bigger potential than what you currently are, and simply by approaching you and voicing their thoughts already more than prove that they obviously care about you, and if you're lucky, probably your progress. More often than not, they are the ones you could rely the most. To be fair, though, this still depends on a case by case basis.
Whether you make it or break it, in any companies, it really all simply depends on how you react to situations. Have a cool head at all times, and you'll do well. Even if you make a huge mistake today (not to the point where your supervisor got a 2-day scolding), well, it might not actually be as big as you thought it was. Also, people don't always remember your mistakes, they'll remember mostly what you do consistently because to err is human.. Have a great journey in building your career!