Do you think I am bipolar?

For a long time I have been very depressed. But I always thought that I didn't HAVE depression because sometimes I get so hyper and happy that I feel like maybe that's just how I am. But sometimes I get so sad, I cry for hours, having hiccuping after effects even though I've already stopped crying a long time ago. I have been getting very suicidal lately...and I don't know why. Each day feels like it gets worse even nothing is changing in my life. I'm not emo or goth or anything, I'm just a normal teenage girl who goes to school everyday...But I don't feel normal. People tell me that I get irritated to easily...And I know I do...Sometimes I'd be very grumpy and then the next second I'm so giggly even though nothing has really changed to make me happy...Sometimes I feel so much hatred to everyone else that I just want to be left alone. And then sometimes I want to talk to everyone and I would get sooo talkative, trying to find anything to comment people on or trying to start a conversation out of one random question. I get so tired a lot and lately I've been having a lot more back pain then usual but like I said, nothing in my life has changed. I used to be a straight A student but since last year, my grades just started going downhill..I dunno. Sometimes I think it's just me. But I have tried to get help at school but when the teacher talked to me all I could say was that my dad lost his job...I couldn't even say that I felt depressed because I'm so shy towards people...And so I guess she thought I was just feeling sad that my dad lost his job and that I wasn't really depressed. I felt so DUMMB! But I do think I'm depressed. I've asked my friends if they ever feel the way I do and they say they sometimes do but they say they would never try to attempt to kill themselves...I have tried to give clues to people on facebook...but ppl would just comment saying things like: "EMOO" or whatever. So I stopped. I feel so...lonely sometimes...Sometimes I think about doing crazy things like crash into another car when I'm driving or to run away or to jump out of a car while it's still moving. When I was younger, I thought about killing myself by drinking bathroom cleaners...But I never had the guts to do so. I have cut myself several times over the years...but I get scared people might see it and call me emo. And just When the time I thought about OD on pills, my boyfriend made me change my mind. I regret it. I mean..I have gone through some bad times... My brother and my sister tried to kill me once. My brother got mad at me and then I ran to my room and he chased after me with a kitchen knife. As I tried to block my door (because I had no lock) he tried to slide the knife under the door where my feet was..so I climbed the wall (there was two walls by my door) so that he couldn't get me. Then one time my sister got very mad at me and hid a knife behind her back. As I was walking out of my room I saw her and asked her what she had behind her. I went to look and It was a knife...So I grabbed it quickly and yelled at her. I never told my parents this though. Then one time my other sister got so mad at me she beat me up until my head bled...I cried so hard that I biked away from home for the whole day then I came back later at night. And then when I was younger.......I was....raped by my ex-boyfriend. But...I don't really want to report it. Because It's too late and he was under 18 and I don't even know where he lives or what his # is anymore. Sorry for writing so much....what do you guys think?