See, that's the problem with a lot of mental illnesses. Most people can't really tell whether they're hormones or actual illness, especially if they come on in the child, adolescent, or senior years, which, with all the new and different chemicals being released into the brain, can cause an imbalance easier than in, say, a stable adulthood.
A lot of people pass off real mental issues as hormones too, which can lead to feeling misunderstood, doubting yourself (like, whether or not you really are doing it for attention, I had this problem a lot before I was diagnosed), and it's one of the contributing factors to young suicide, especially in teenagers.
There's a difference between your typical moody teen and your clinical bipolar teen. The average teen wouldn't go from a violent frenzy to a depressed calm at the drop of a hat, say.
Maybe you should look into it a little more, get a few more tests done. These days I find a lot of doctors are a bit trigger-happy with diagnoses. Perhaps a few extra opinions would help to sort you out, and better your understanding of the difference between illnesses and regular mood swings. 3nodding