My Dad Lashes Out

My dad is usually lovely and he is supportive of me, and i know that no one is perfect. The back ground story is a bit pathetic but here goes. I was telling my dad how a volunteer at the library couldn't stamp the books correctly, it was a trivial family conversation.
He tried to tell me  'maybe she's struggling and is a bit dim', so i explained it was a joke. I walked off to avoid a confrontation and then he called me back and started yelling at me about how the whole street could hear the conversation. At this point i thought he was overreacting seeing as it was only meant to be a joke and we've all passed judgements on people so I made a sarcastic joke i thought would be funny and then he was chasing after me, grabbed me by the shoulders and pushed me to the ground. I fell onto the sofa so he slapped me, and then tried to scramble away up the stairs. He then kicked me up the stairs (literally) and when i fell over, grabbed me and told me to get up and stop screaming. I have a large cut all the way down my knee and bruises from where he grabbed. My face has a horrible slap mark across it and ive grazed both knees via carpet burn.
I'm 14 and this hasn't happened since i was about 11 but it always happens this bad. He looks so angry and i feel so small. I would'nt normally think twice about it but i have P.E tomorrow and i don't want the girls at school asking questions about all my bruises and cuts. I really don't want to come home tomorrow, am i overreacting? Should i be afraid of my own father? 
CharlieBucket CharlieBucket
18-21
May 23, 2012