I Think I might have Bipolar Disorder?

A freind recently told me they have bipolar disorder and that they think I might have it too, after some research, I became more convinced I have it. I Get really depressed, alot of the time for no reason. I have lost interest in lots of things I used to enjoy and I often feel like I'm worthless. I feel like I want to kill myself (even though I never would) and I often feel numb and dazed, like Im unable to notice very obvious things, Whats Going On?