if you saw a clot you need to call your ob/gyn ASAP! clots are NOT good during pregnancy.
there were a couple of times when me and my boyfriend would have sex and right after we were done i started bleeding..
it could be from your cervix since its producing extra blood .. when it gets touched thats when you see blood .. thats what the ob.gyn at the hospital told me .. but i would get checked out just to be on the safe side ..
its never good to see blood while your prego - i would just double check with your ob.gyn!
good luck!