Weird feeling in lower abdomen

I have been experiencing weird twinges or flutters in my lower abdomen, mostly on just one side. At first I thought it was baby but its been constant for a couple hours now. Moving and changing positions doesnt make it stop. I'm 30 weeks so I definitely know what it feels like when my baby kicks and this isnt it. I can actually feel baby kick every once in a while closer to my belly button so I dont think these feelings that low would be the baby. Any ideas what could be going on? It's kinda annoying and is actually making me a little nauseous. It isnt painful though. Has anyone else had this happen?