Yeah, I had bleeding when I was pregnant with my first; doctor said it was fine. As long as your water doesn't break and your contractions don't start.
just try to take it easy ...
Ya my gf is 30 weeks and she was bleeding alot but the doctor said its normal and another way to induce u into labor lol thats what happened to my best friend
Sex can sometimes cause a irritated cervix which causes light bleeding. It depends on how gentle you were. It shouldn't last too long but if you're worried I'd just run it past your doctor to be on the safe side. Best wishes x