Spotting after stopping the pill?

So I went to the doctors three times this week for pelvic pain, cramping, lower back pain and frequent urination. I didn't tell the doctor I've also been moody, had headaches, sore breasts, and fatigue because I thought I was ovulating and I usually get those symptoms around that time. I was diagnosed with a cyst because everything else came back clean. She told me to stop taking the pill which was four days ago. The last three days I've been having extremely mucus like discharge. I'm supposed to start the nuva ring today so I took a pregnancy test just in case because last year when I got a cyst I found out I was pregnant about a month after and I was glad I found out because I was supposed to start a new birth control a couple days before but I hadn't yet. So this test came out negative. But then when I wiped there was blood. I had my last period on November 19th. My husband and I only used the pill and since I stopped we've only had anal sex. Was this blood caused from stopping the pill? Should I start the nuva ring today or wait and call my doctor tomorrow?