Hey Maven,
I don't think you need to give up your career goals or going to college. I still think you should look into taking a lighter course load. Or maybe your school has some physical classes? At my current school, they're big on physical education classes. You could also look around in your community for some fun physical activities to do to help you get in shape. I like ballet, so I take adult ballet classes when I can. I go to two different schools and have a wide variety of levels to pick from. A lot of the adult I dance with are either older dancers just having fun past their prime and regular adults enjoying ballet to help lose weight and stay fit. Your community might also have some local acting companies. Have you auditioned for any parts or anything? Even small parts will help you gain experience.
If you do some of those things, and are able to enjoy them, you might find it easier to go to class. You just have to make sure you leave enough time to get homework done, and stay rested. I find it easier for me to budget my time and go to classes, appointments, etc, when I have more things going on. There's a fine line, though, between just right and way too much, and that's what I have trouble finding.
I hope this next semester you enjoy your acting classes! Just remember not to beat yourself up and be to be gentle on yourself. You can do it!!