Why is my discharge like this?

Since yesterday I have discharge that looks very mucus like. I'm not pregnant (hopefully). I was on the pill and taking it 100% correctly until two days ago. We've only had anal sex since I got off of it and yesterday we used a condom too even though we finished with anal. I've been to the doctors 3 times this week because of pelvic pain, cramping, lower back pain and frequent urination. The doctor told me it sounds like a cyst. That's why I had to stop the pill. I'm starting the nuva ring tomorrow but I'm going to take a pregnancy test with fmu just in case. But I just had my period November 19. I'm also 3 1/2 months postpartum. Is this normal?