dreamrunner, I agree with what bipolar bear just said.
Plus there are different types/degrees of Bipolar, not everyone requires the same meds or dosages. And again, I do not think a GP should be writing prescriptions for Lithium, but that's my opinion.
I too never had what I would say is hypomania and/or mania, basically just had extreme depressions, but after very close evaluations and observation, my former psychologist and psychiatrist came to Bipolar-II(mild) and ADD(mild) DX for me. Did the various meds thingy, and after several, Lamictal did the trick, no deep depressions which the AD's (SSRI'S) that my GP had prescribed in the past lost their effectiveness. It may be in your best interest to get a 2nd opinion from another pdoc, whatever you decide I am wishing you lots of luck with this, and always feel free to come here and/or PM me.
Take good care now,
DE