Stomach tightening at 22 weeks

I have started noticing a few times a day my stomach will get really tight/ hard and I can feel where baby is. It doesn’t hurt at all. I especially notice it when I’m gassy. It isn’t close enough to time or anything but I have noticed it maybe 6 times throughout the day today. I also have lower back aches/ cramps.

Also noticed I’ve had a lot of discharge. Tonight it has been very mucus like and stretchy. Kind of a green yellow color.

Is this normal? Should I call my Dr or can it wait for my appt in 3 weeks?