Please help.. is this depression?!

Please help.. is this depression?

It started about 7 months ago when I started cutting myself. I'd feel really low and cry myself to sleep just a couple of times a month. I thought it was just a phase and would just go away, but it didn't. It's gotten worse, and I've been feeling extremely sad and... I don't even have words. I just hurt so much. And the weirdest thing is, when my best friend would tell me he would be hanging out with someone other than me, I would get extremely mad at him and scream at him and tell him it was his fault I'm like this. I don't even know what could've gotten into me. Months ago, I never would've done something like this. The cutting is worse than ever, and I just feel... hurt... everyday. Ways to kill myself have entered my mind more than once. Whenever the smallest thing sets me off, I get into angry/upset/crying mode. If this is just a phase, it's a really long phase that's affecting my relationship with friends and family. Please help.

you either have major depressive disorder or you could be bipolar. in any case, dont take my word for it, please go to a psychiatrist at once. u need help, and i think you should go get it at once!