Back pain or labor contractions? Help! (FTM)

Chelsea
I'm 38 weeks, 1 day. So as of bed time last night, I've been getting horrible back pain. No position helps it. It didn't seem to last long, maybe 30 seconds to 1 minute, then stops. I deemed it gas pain from dinner, took some tums last night and went to bed. However, I woke up all night to back cramps and kept getting up to use the bathroom (just typical mid night pee runs) and move. I've started timing them this morning as they still haven't stopped and they are 6-8 minutes apart with the occasional skip where I don't have any. I don't feel much pain in my stomach, some tightening... Just a lot of pain in my lower back. It doesn't seem to be what I read about labor, so I really don't know. I don't want to call the SO home from work or drive 50 minutes to the hospital just to be told it's gas or constipation... Any experience? It's also the first issue with potential contractions I've had. I didn't really get many Braxton hicks, definitely nothing painful...