I had two periods and bled once or twice after sex in the first 12 weeks. If it continues go to er. Bleeding some is common. But it's always best to be safe!
Bleeding early on in pregnancy is common for some women. I would not be too concerned if it is minimal and you are not having any other symptoms. I would keep a close eye on things and if the bleeding gets heavier I would call the doctor. If you are concerned now there is nothing wrong with giving the doc a call.
It may be too early to tell, but I'll pray that the baby is fine :-)