Contractions?

I just sat through a 2 hour meeting at work. About 50 minutes in, I got pretty uncomfortable lower back cramps (period like). It kind of felt like I had to go to poop so I went to the bathroom but I didn’t have to and the feeling went away. Then about an hour later the lower back cramps came back. They moved to the front too. I didn’t really notice if my belly was hard or not when this was happening. The meeting ended and I walked to my car & I felt sore and achy under my bump. Are these contractions or just discomfort from sitting for too long?

I’m 38 weeks 3 days and a FTM.