What Causes Severe Pain And Pressure In Pelvis Along With Vaginal Discharge During Pregnancy?

Hi I am currently 27 weeks pregnant and im havin a lot of pelvic pain and pressure. I also have lower back pain and am having a small amount of discharge as well as my stomach getting hard. This is my second pregnancy and im not sure if i should call my obgyn or wait it out till I see him on Monday. I have tried resting with my legs on a pillow but pains dont go away. Ive been like this for almost 2 hours now.