Is this possibly BP? Please help.

Hi there.
I am at risk for paranoia, scizophrenia and depression (it runs in my family), and I've been noticing recently that the depression is starting to take a turn for the worst. thre was one eriod where itw as absolutely crushing, but generally its just moderate to strong feelings of being alone or worthless, generally at night, even if i've had a full day of hanging out with friends, etc.
Anyways, yesterday, I was extremely hyper at my house (which figures, my friends were over, halloween, you know), then we left and went to my friends house, where my energy just died. I was extremely tired and then we walked to the McDonald's, where I had extreme feelings of anger and hostility. I actually hit my friend into a door beause of it.
Then today, I was feeling normal when I got home, then became depressed, for about half an hour, after which i suddenly became extremely hyper, and felt like I could do anything. I stomped around the house, trying to rip my student card apart with my teeth, and then went downstairs, where I paced for 15 minutes until I started to feel trapped. I left my hosue and got my friend, and then retained that hyperactivity (which also included agressiveness) for the rest of the day.
Any opinions are welcome.

What you describe can be bipolar, but could be other things as well. I've seen teen agers act that way many times. A medical person is the one who should diagnose bipolar. Usually the symptoms should be around for at least a few weeks. The bipolar state is often characterized with not sleeping very much and with a lot of activity. The person often talks a lot and spends a lot of money. But there are many different kinds--a medical person is the one to judge these things after a good examination.
Good Luck,
Jim S