I did the exact same thing, like to a T. i had no control over myself , i had just lost it.
after i freaked out like that i cried myself to sleep and woke up fine, as if nothing had even happened. I have no idea why, i just snapped after my little sister pissed me off. i wish i could help but i am in the same boat, i am on meds for bi-polar disorder and anxiety, but it didnt help. If you arent being treated you should really go to a psychiatrist and confirm that its bipolar so that your family will know why this is happening. I have read that this is a common symptom for adolecence with bipolar disorder. Stress will set things off, so look for ways to avoid stressful situations until you get professional help.
And you arent crazy by the way, with help you will even out with the moods.

take care xo
jess

I'am not a jesus freak but I can tell you to maybe seek God and ask for help.

im like that too, but it varies in how much my mood changes, sometimes it wont change that much, but still noticably, and sometimes it goes from the best mood in the world to as angry as a person could ever be. im just trying to avoid anything stressful like that (which is hard when you have friends and family like mine) and im searching for someone to talk to about it.

eek. I do this too, only I dont come out of it so fast.

A few times i've ended up being so mad and frustrated that I yelled at everyone to the point where my Dad got angry and my frustration turned to fear (he's never hurt me though) and I litterily screamed at the top of my lungs for the longest time. I threw a glass cup at him and it exploded everywhere... it was self defence. Well I thought it was at the time.

And my parents were calling me a spoit brat the whole time saying I was acting like a toddlier. "It's a battle of the wills and i'm going to win!" said my dad. I just keep screaming in terror. I wish they'd get it!