upset stomach or false labor? 37 weeks

So I was sitting on the couch watching tv when my back started to hurt really bad. Nothing too crazy but couldn't even stretch out and get comfortable. Then I started having this nauseous feeling to the point where I thought I was going to puke and still do feel like that. Stood up to walk out to kitchen and just felt like radiating belly pain. So painful so I decided to go up and sit in a little warm bath to try and find a comfort zone. Still having belly and back pains when all the sudden I had to hop out of the tub and go straight to the toilet. Had a very loose BM and now sitting back in tub. Is this upset stomach or is baby near? Or is it just false labor? I'm 37 weeks and 1 day