Hi, I'm no expert on anything, but I have a few thoughts:
First, it seems you have a lot of anxiety about school, maybe stemming from wanting to hurry up and finish so you could get the job you want and improve your life. I think what you're doing with your studying by getting ahead is great, and I commend you for that. But just remember: what's important is the grades you end up getting on your exams and assignments, and ultimately your final grade in the courses, and that final grade is going to release at the same time every single time-at the end of the semester. The point is that getting ahead with studying is only going to help you with your studying and getting better grades on those exams... but its not going to fast-forward time for you. Those exams are still gonna be spread out however far they are, and that final grade is still going to be released at the end of the semester so you're still going to have to live through your days in the meantime until those days come, and you won't be able to just skip over time and get those grades back any faster by over-studying and having it consume your mind so much. It's almost as if you're mind is subconsciously just sick of where you're at currently in life (or have been) and you're just wanting to get to the end of the academic-road ASAP so you can get your shit together. And as a result, you're obsessing about studying, how much you study and how much to get ahead. Now if I'm wrong about this and you've already had a great and successful career, had your life in check for years, etc, then excuse me, I'm only speculating because I went through something similar when I first decided I wanted to go to college.. I was fed up with where I was in life and when I eventually started my first few semesters I was just so eager to improve my situation and finish the classes that I needed for my degree that I had similar episodes of obsessing about studying.
Anyway, just relax and take a step-back from beating yourself up about studying, because that's what you're doing. It's completely irrational, because, it's not as if we're talking about someone who hasn't done shit all semester and is cramming for exams a few days before an exam and HAS to have this huge sense of urgency that you currently have, because they'll without a doubt fail without it. We're talking about the complete opposite! Someone who is not only not cramming last minute, but keeping up with the material, and not just keeping up with the material, but you're well-ahead! So with that said, you're beating yourself up and being overly harsh on yourself in this regard for no reason.... you say that sometimes you hit a wall. Well of course you do, you're studying like a mad-scientist! Your brain needs breaks, of course it can't take any more. You say it's a matter of mental stamina....you have plenty of mental stamina, otherwise you wouldn't be keeping up with the material like you are and you'd be cramming for the exams in the last few days. So, instead of over-studying and obsessing about making sure you're actively studying at all moments of every day, you need to just focus on making sure you actually 100% understand the next material you're going to be tested on.
You're burning yourself out, and since you cant fast forward time you'd be so much better off by not worrying about making sure you're studying 24/7, cause that isn't going to get you towards your dreams any closer. What will is getting A's on your exams, so spend less time getting ahead and filling your days with nothing but studying just so that you could be studying for the sake of studying, and spend more time making sure you're comfortable with the upcoming material that you'll be tested on. If studying is a hobby to you right now and you enjoy it so much, then try to direct that interest and energy towards mastering your current material. With how much you're obsessing about studying just for the sake of constantly getting ahead of the material, you could learn the current material that'll be on your next exam inside and out, which will ensure you get an A on the exam, which is the most important thing at the end of the day.
But I know it's easier said that done, because as you said you're fearful and anxious about taking breaks from studying because you would rather keep studying and feel like you're wasting time. You need to try and figure out how to deal with that anxiety so that you could eliminate these feelings. There may be some "natural" things you could do to assist with this. You said you don't take your Adderall every day, so maybe on your off-days you could try something like CBD oil. It's non psychoactive and supposedly can help with anxiety and to induce relaxation. See if that could help alleviate the anxiety about feeling like you're wasting your time. Or you could start a new exercise-regimen, or anything else that may possibly reduce anxiety.
Regarding your last paragraph: you recreationally taking the Adderall so late in the night while playing video games and chilling could be due to another issue, like depression. You did say that you were alone. With taking adderall at night, and wanting to drink with friends to blow off steam about your anxiety, it could be possible you may be tying to self-medicate somehow.
Because you've been fixated on this getting ahead with studying idea and creating extra pressure on yourself when you're not studying, which also may be causing you to be experiencing some anxiety/depression, it could be that you were relaxed by the adderall at night because you using it to get away from all of that.
Nobody has to tell you, you said yourself you know that continuing to have those adderall+video game sessions late at night is destructive behavior and really bad for you, so you already know that. But maybe instead of doing that, you can try to pick up some different hobbies on days you're taking breaks from studying? Something like that may naturally cure your anxiety/depression too. I mean something like going to your local park for a walk, fishing, starting a new book thats not related to your coursework, etc. This may benefit you psychologically.
Remember if you continue to have these issues then you should reach out to your doctor/psychiatrist so that they can offer you professional help, and try changing your medications, or having you undergo some CBT, etc.
Goodluck, I hope everything works out for you.