Abdominal pain

Elizabeth • 25 years old. TTC #1 after miscarriage in 2012
I'm 20 weeks + the day and the last 48 hours I've had horrible abdominal pains. Yesterday after lunch my stomach started cramping really bad which kept me in the restroom most of the afternoon. I eventually had an episode of diarrhea and for the most part started to feel better. I stuck with blan foods for dinner and sipped on some ginger ale to help calm my belly. This morning I felt better until I ate breakfast (a bowl of Cheerios and orange juice). I haven't used the restroom yet today but I have the chills and my stomach hurts really bad. I'm extremely uncomfortable and just want to feel better. I called my obgyn and I'm waiting on a call back. I'm not too concerned about the baby because I felt her moving like crazy last night so I'm sure she's fine, mama is just under the weather. Any advice?