Cramps after walking

38 weeks today.. went for a 20 min walk. Probably less than a mile. During the walk and now after for 2 hours I’ve been so crampy. It’s pretty constant so i know it’s not contractions. It’s down low across my whole lower belly. I guess comparable to period cramps. Anyone else get this from going on a stroll? Happened last week too. Hopefully it’s at least helping dilate me.