Bad cramps!!! Advice please!!!!

I'm 12 wks pregnant, and yesterday after I had sex, I had really horrible cramps.. I googled it, n it said it was normal, n it would last 1-2 hrs.. Mine however were severe for 2 hrs. Where it was hard to even walk.. Then the pain was still there, although bearable, I still had them for another 12+ hrs!!! I have no bleeding n its in my lower them in abdomen.. Has anyone else have this!! Should I go to e.r?? Or could it just be gas??