I haven't had sex in a year and 1 month , until last Friday , I had unprotected sex and every since then I've been having stomachs cramps , can some please help on what this maybe or guess !

See A Dr!

I would venture to guess it could be a coincidence, like gas pain. Either way, a week after sex will not likely be pregnancy or STD related if that's what you're thinking. See a doctor, who can do the proper physical exam and labs if necessary.