Where do you draw the line between Bipolar Disorder and teenage "moodiness"?

I mean, I know teenagers can be moody, but isn't there a distinction between the two? I was diagnosed with Bipolar when I was 12, but I had a lot of friends and doctors who didn't believe me and chalked it all up to "hormones."

I just wanted to know everyone's opinion on the subject--between moodiness and a real mood disorder.

In my opinion (not that it really matters, because I'm only 17), this is the distinction between the two: teenagers tend to become overly emotional about events that may not elicit such an extreme response, but are nevertheless justified by their own reasoning. I think they find things important that, in reality, aren't very important. I've seen friends become "depressed" over breaking their cell phones, or because their bf couldn't go to the movies with them that Saturday night. Grated, these events aren't pleasant, but they certainly aren't the end of the world, either. To me, this is "moodiness." A mood disorder doesn't need any event--it just happens, with no real justification. I'm elated, and I don't know why. Heck, I could have just cut my arm off, and I'll still be manic. The other extreme is also true: I could win the lottery and be too depressed to even cash in the winning ticket. It's almost as if my mood is entirely independent of my circumstances. My "mood swings" can also be really extreme--hysterical, crying, elated, despondent, impulsive, suicidal--and again, there is no real "event" that would elicit such an extreme emotion. It just feels like my "mood swings" are more debilitating than the average person--but then again, maybe I'm wrong and everyone's like this, and they just hide it a lot better than I do.

Anyways, those are just my thoughts. What are yours?