Is Having Yellowish Vaginal Discharge Post Sex While On Depo Normal?

Hi, I am currently taking depo provera birth control. A few months ago while taking depo I had a misscarriage. I didn t know I was pregnant. Since then I ve been sexually inactive. Until Tuesday night. I ended up having unprotected sex and he did cum inside of me. Today 36 hours after the event I took the plan b pill just incase. This evening I started experiencing a lot of yellowish discharge? Is this common and are there other side effects that are normal?