I've been feeling crampy and some pressure lately too. I'm 35 weeks and my dr said it's from everything opening up.
To be honest u really don't know but I feel those same symptoms and I'm only 31 weeks. Keep in mind I've been on bedrest and haven't had a great pregnancy what so ever. You should call your doctor and ask them what oh should do or if they think it's anything that u can be seen for
I think when your cervix is effacing (thinning out) it can feel like that. Effacing is different than dilation but it is still part of the process. I had that for a few days before active labor started. Things are happening but it doesn't really tell you when the real show will start. When it does, most women know because it is obvious.
I've had all of that for 3 weeks now, it's just your body getting ready for labour :-) Try to get some rest, take paracetemol if you need to.