Stomach ache...

Hey ladies so yesterday I ate something that isn't sitting well in my stomach..its been crampy since last night till this morning. I'm worried that it's something serious and I don't want it to hurt my son. I myself don't feel bad just feel like I have to go #2 to get it whatever it is out! Any suggestions on how to make it feel better? And should I be really concerned? Or is this just apart of pregnancy. I'm 37 weeks...thanks!!