Well I guess it depends on how you feel. If you think you can handle 12 credits it is your life after all. I think if you decided to stay for a semester you should keep a stable relationship with your T and make sure you take classes that aren't too intense and that you have the support you need. I didn't know I was bipolar in college but what worked for me personally was taking all my classes on Tuesdays and Thursdays and I would do homework on Wednesdays. That way I would have Friday-Monday to kind of take it easy and recover. This might not be the solution for everyone but I think you just have to figure out what you can handle and what you can't and go from there.

I can't tell you what you should or shouldn't do, that's for you to decide, but I do think that doing things just because others want you to tends to breed resentment. If you take off a semester it has to be your decision because it feels like the best thing for you, not because your mom or T think so.