What Causes Pain And Bleeding After Sex?

I just had sex. My boyfriend went a certain way and i felt pain! I got very wet and didn't notice nothing until after when i saw alot of blood on he blankets i checked myself and i was bleeding inside. I got off my period a week ago! It has been about thirty minutes and i still am bleeding but not as much! I feel dizzy and pain on one side! That side feels very weak and shaky also.