need advice. not sure what to do when a Dr misdiagnose my daughter

I have a 10 yr old daughter that has adhd, and she''s been seeing a Dr for 6 ys, untill July of this yr. the Dr had told me that she was manic, schizophrenia with bipolar, and she gave her new meds (lithium 300 mg 2 a day) so I tried giving it to her for 4 days and it made her deathly sick, so in between appointments I called back & told the therapist what was going on that my child was sick & acting funny her eyes was twitching, her muscles was hurting & diarrhea, so I said I''m stopping this meds, so I did, then we went back and I asked her shouldn''t she checked her blood because I think it didn''t agree with her, and she got upset and dismissed her as a patient & wouldn''t give her any meds and I explained to her what is she gonna do that she was use to taking her other meds and that she had to go to school, finally I had to take her to our local E.R. because she was going Thur withdraws she was very sick, over something that could have been prevented, I''m not sure what to do..