Hi Melissa. Hold on tight.
Yes, antidepressants can be extremely destabilising for some bipolar people. I'm one of them. Prozac had me in manic agitation in under 6 hours of starting it, and I experienced severe mood swings within a week. By 2 weeks I was in a full blown mixed episode with wild excitement and intense despair I can't explain to anyone who hasn't been there. My pdoc took me off Prozac after 3 weeks. Now 9 months later, I have been on mood stabilizers (valproate and lithium) and I have mostly discrete moods of hypomania to mania with hallucinations, to depression. I am now only occasionally suicidal, but my moods are frequently mixed. The cycles have slowed down from several switches a day to a peak every 3 weeks.
Be very careful with antidepressants if you feel anything is suspiciously unstable. The after effects can continue for a very long time.