Hey Bpchick! :o)
Listen, I would seriously have a discussion with your doctor about how you responded long ago on Lithium and the troubles you had with your concentration and school. Let him know that you are planning to go back to school and that you don't want to face the same challenges. You have just as much say so about your treatment options as your doctor has.
Tell him/her that you would like to try other options first. I have been on Depakote and that worked well for me but I too didn't like the weight gain. I tried Lamictal and that worked for a time. Now I am on Geodon and that has been pretty stable for me. My pdoc just switched me from prozac to wellbutrin and I have had a tremendous improvement after being 2 years trapped in the "adjusting and tinkering with my meds" syndrome.
I just want you to know that there are many medication options for you. It may take time but eventually you will find something that works for you. It took me 2 years! Not to discourage you but to let you know everybody is different.
Have a serious talk with your doctor. Good luck to you and keep us posted here.