Labor signs?

39w3d FTM, I have had Braxton Hicks for the last 3 solid weeks. Pretty much 20-40 mins apart (they’d get super close if I was active then go to almost an hour apart when I rested).

This morning around 5am I woke up to a horrible lower abdomen cramp/pain. Then woke up every 20 ish minutes to that pain and contraction of uterus, plus horrible lower back pain. I started to time them around from 8-9am and they were about every 10-20 mins.

They haven’t gotten closer or suddenly stronger but they do feel different than the Braxton Hicks I’ve been having.

Any theories? Thanks.