I'm 31 weeks pregnant and just the last few hours I've got a feeling of tightness or mild pressure in the very bottom part of my bump. At first I thought it was just discomfort from my PJ bottoms digging in a bit as they're not maternity ones, and it does seem to be a bit less uncomfortable when I hold the band away from my bump, but it is still there. Is this something I should get checked out pretty urgently or just normal stretching etc? It's my first pregnancy. I've got my belated 31 week appointment with the midwife on Monday.