I would say make small goals for yourself. They don't need to be giant goals, and although your goal might be "turn the whole semester around," that's not realistically going to happen in a few days. So make goals like, "I will just go to class today," or something like that. I don't know if that seems too hard to do. But you get my point. If I were in your shoes I'd make small goals like that. Or they don't even necessarily have to be school-related goals, they could be goals like, "I will exercise today" or whatever you do to benefit your mental health. I would say that through a lot of small actions you can eventually persevere.