Bad cramping

Okay so I'm 38 weeks and 2 days now and I'm having some pretty painful cramping going on. It feels like I'm about to get my period, just a little more intense. It started in my back but now it's in my back and lower abdominal area. Mainly on my left side tho. I've been having irregular contractions for a few weeks now, I actually didn't realize that I was having them until I had nst done at my 36 week appointment. I just don't know what to think about this cramping pain. It's not unbearable but it's definitely not comfortable at all and gradually getting worse.