how long have you been on medication for now?
i've been on for a year or so and I still struggle a bit with it for similar reasons, it takes time to learn how to cope with for sure, but with time it becomes less of a bother
For a while the biggest problem I had was feeling guilty if I actually let myself relax while on medication, but it's important to do so as well, you can't do everything at once, you need to manage your time as best you can and stressing yourself out by constantly trying to do productive things can be bad as well
You'll learn how to structure yourself with time but I know exactly what you mean about feeling nervous/freaked out sometimes because you're used to failing and 'paying for it', sometimes that gets me before I even start something even to this day, it's hard to undo years of negative reinforcement that makes you feel bad about yourself for even trying, even when you start to see results
therapy could help if you were inclined to do that, I find just talking about things with someone occasionally helps a lot but I can't afford therapy on top of everything else at the moment so I usually just go to www.7cupsoftea.com when that stuff gets to me and have a chat on there
a few tips on how to structure yourself by the way, and this may help a good deal but you still need to apply yourself and get into a good habit of it
Calender: Plan out a few weeks/months in advance, put down your assessment dates etc, this helps so much with knowing where you need to be at with things and gives you general 'structure' in stead of 'okay out of all these things I could do, what should I do?'
Todo lists: This one isn't as effective for myself but it helps to have one in clear sight, reminds you of your priorities and it feels great to cross things off, even if you don't do it immediately
Day to day time structuring: this one is a lot trickier to start and get into a habit of, plan out a day in advance and set yourself a routine for the day, start with when you anticipate waking up, having breakfast, set aside an hour or so for every activity you need to get done in the day, allow some rest time in between activities. I used to do this a fair bit, it helps A LOT but in the end I couldn't keep up with it because I kept changing things up. Theres a lot of good apps that can help you set this kind of thing up though, and it's great if you combine it with the calender and to-do list as it really sets you up to know what you need to do at any given moment
When studying:
Learn new studying techniques, learn either the Process Reading method or the SQ3R method, these will help A LOT when it comes to studying, reading and all that, and it cannot be overstated enough, study on paper or at least take hand written notes., even though typing is easier, taking notes by hand helps a huge deal.
USE POMODORO TIMERS Don't study for more than like 50 minutes at a time without a break, any longer and you'll start to lose efficiency even if you still feel focused, I personally choose to break mine up into 25 minute studying, 5 minute break blocks of time and it feels so much more effective than when I first got on medication and tried to just work it all out without any real time structuring, actually learning a lot more and a lot more effectively in a shorter period of time as a result of that and the SQ3R reading approach
Lastly, something I want you to remember, don't put too much pressure on yourself to get it right all at once, it will take time to get on top of things, at which point you also need to learn to stay on top of them, this will take time, medication only offers you the functionality, but it doesn't teach the skills you need to really succeed, that's something that you won't magically get just because you're on medication, it's something that you will learn over time and you WILL fail and fall a few times in the process, accept this, and don't be too hard on yourself about it, don't beat yourself up for making mistakes, don't try to be perfect about it, the problem with the newly found functional mindstate in my experience is that it can create a lot of anxiety towards failure in having known that for the majority of your life, you know you're capable now of truly improving things, but you naturally get into that mindset of overestimating just how much improvement there is simply because of functionality.
I take it based on your post you're still relatively new to medication and the functional state of mind, so i'm not saying this to discourage you, just reassuring you that while it will be a lot easier for you now, it will take time to learn to cope with it all and that's absolutely okay, that's a part of growing up and becoming a functional adult, you can't rush it, you can only do your best and anticipate that it will take time and it is a bit of a trial and error process to work out, in accepting this it will help you a lot to not just give up and get down on yourself along the way