Bipolar disorder is notoriously hard to diagnose. I believe my own case is typical. When I was in a manic state, it never occurred to seek help. I was either feeling great or generally pissed off at the world and either way wasn't interested in seeing a doctor. I only went whenever I was too depressed to function so I was treated for depression and once that happened it was tough to shake the idea that I was depressed and not bipolar. That continued for years until it became obvious that meds for depression just wouldn't work for me.

I finally found info online, here in particular, that lead me to believe I was bipolar so I went to my doctor and sort of lead him to ask the right questions so it wouldn't be a case of me self-diagnosing. But that was only after about 5 years of being treated for depression. In my opinion, your best bet is to see a doctor and be completely forthcoming about your feelings.