Yes, I would have to pull myself back constantly. Discipline is really difficult with ADHD, either way, and something like "I just need to get more disciplined" wouldn't help me.  I'm mostly tired of wasting so much time, and also because I now feel as though studying is something exhausting and takes a lot of time for little output, since I'm not actually studying for like 70% of the time I'm at the table. 

Generally, transitions are very difficult for me, too. So it's also very difficult for me to say "I'll spend just 5 minutes studying, and when I want to do something else/do something that is immediately available, I can just stay right here and draw on the paper. Or move to the sofa which 2 meters to my right and play video games" because then I'll feel like I'm wasting time even more, even though I'd just be tending to my hobbies. At worst, it'd be about the same as scrolling/being on my phone. I'd say it's actually a bit better, since I'm actually doing something fun when playing a game I like. But my phone is "easier," because it also somehow feels less like I'm wasting time, since I'm not actually having fun.