Gas pains or something else

Ok I have a serious question that sounds funny. Since last night I have had what can only be described as swimmers cramp type pains in my lower abdomen. It was so bad this morning around 1:30 I couldn't move it was tolerable all day. I pooped twice but now it's hurting like crazy again. I've taken mylanta to help is there anything else you can suggest. It feels like my stomach is full of gas but nothing will come out. I'm 18w4d