Pain at 16 weeks

I found out that I have an anterior placenta, early in my pregnancy I experienced some uncomfortable pelvic pain which I read was normal. At 13 weeks I felt this heaviness and also pain in my lower abdomen and the doctor told me to come in because I was having brown discharge and that’s when they said I had an anterior placenta. 3 weeks later I’m struggling to walk I feel my uterus is sitting really low, I don’t usually ever experience lower back pain but I am now, and I’m struggling to catch my breath when I talk. Should I call the on call nurse or should I wait it out? I’m almost in tears with the amount of pain I’m in.