33w1d - Need Advice

I’m pregnant with baby #2 and my plan is to try for a VBAC. My first was breech and I got preeclampsia at 39w4d and had a scheduled csection a day later- I didn’t experience contractions or dilate.

So this pregnancy basically feels like a first for me because I have no idea what contractions or braxton hicks feel like..

For weeks now I’ve been having pretty bad back pain which is fine but today I’ve been having period-like cramps that aren’t really coming and going, they’re kind of staying. I’ve had a normal amount of discharge and I don’t have any bleeding. I plan on calling my ob tonight or in the morning if they’re still happening or getting worse but I’m just wondering if anyone has an idea what I could be experiencing??