Challenge your mindset. I'm similar in an autistic way, I need to be in my room to do writing properly. I started to make myself do some minimal amount, like 30 mins and then I'm done and I don't need to feel guilty about not doing more. Place study sessions in your calendar at certain time and make it a daily goal. Start with as little as 5 mins on particular subject but focus on it completely, after you're finished you can slack off. Fit it into your schedule/routine. Get to know yourself, for example I know that shit I hate I must do first thing in the morning because I have strongest willpower in the morning. Other good habit is, if something that I have to do takes less than 5 minutes, I do it right away. Could work with learning particular subjects. Another crucial things for willpower is proper sleep, nutrition and hydration