Need advice

I am 37 weeks 2 days pregnant and for the past 48 hours I’ve been having very bad back pain, I can’t lay, sit or stand. It’s a constant, intense pain and paracetamol is just easing it ever so slightly, baths and hot water bottles aren’t helping. I have been having stomach cramps too but inconsistent, no time to them but when they come they take my breath away. I had a growth scan today baby is estimated at 7lb11, could this be normal or should I get checked?