I knew nothing about mental illness until I sought help from a primary care physician for anxiety and depression, and when SSRI's (zoloft) made things worse, I saw a psychiatrist. When I described my "ups and downs" that I had lived with for years he explained to me what bipolar disorder was, and that I fit that diagnosis. Later I had psychosis.

Moral of the story: I wouldn't assume anything without talking to a psychiatrist about it. But be careful. I knew so much about PTSD that I convinced one of my psychiatrists I should only be on zoloft again (I had to get off lithium because of side effects, started to become manic.) She went with my observations, prescribed me more zoloft and I had a terrible reaction. Keep that in mind, be objective about your symptoms, don't assume it's bipolar. It could be ADHD for instance. (Total hypothetical) Bottom line is let the psychiatrist diagnose what it is, because if you come in with a preconception, they may just go with your preconception.