Mommas please help idk what this means . 38 weeks pregnant

I’m 38 weeks as of yesterday. I’ve had lots of Braxton Hicks for weeks so I’ve been used to that. Last night just felt different. My stomach kept gardening and getting tight for hours every few minutes and we’re worse when I was standing. The pain was so bad in my low back. After hours it stopped and I fell asleep and now I’m awake and I haven’t had any. Why did this happen ??