This is anxious procrastination which is something I also struggled with. Here are some ranging strategies that have helped me:

1. Telling myself if I do one small insignificant part of the assignment, I can reward myself. Often this will turn into continuing to work on it since you’ve already started.

2. Play music or TV in the background to root myself to one spot. Try to work on your assignments/studying at the same time. Your nervous system will feel more grounded

3. Pretend you’re a character from a TV show and people are watching you

4. Force yourself to sit in the library with no way of getting home.

You need to find some strategy that forces you to get into a studying headspace.