It sounds to me like you might have some anxiety going on, and maybe some other thins, too. You should see a psychiatrist, to be sure. - Blu
Have you actually been diagnosed with bi-polar? I can only give you my opinion from what you've written, and because I'm not a Dr. To me, it sounds like depression and anxiety. Even though you have'nt been overly stressed you have been stressed. That cause cause anxiety. It can also cause depression.
Are you in therapy and or taking meds? If not, I would highly recommend therapy to help with your anxiety and possible depression.
We're here to listen and help anyway we can.