I just had my period and 2 days later I had sex. During sex I started bleeding just for few moments and it stop. However, 2 days later I still have a little cramping.

I know that your period will come back sometime after sex if you don't wait lon enough. Is that possibly what's happen ?

Its happened to me... if its just a little bit, then no worries, it most likely is just you coming off your monthly.. now if you have sex again, and it does it again.. you should go to the doctor because you could have some sort of infection, maybe the beginning of a bladder, or kidney etc... sometimes that is even how you notice the signs of cervical cancer.. that is how I caught mine. So good luck to you, and just keep an eye for signs... and go to your regular checkups