Deop Shot

Patient: I had my daughter in May of 2010 and after a while I had stopped taking the depo shot until I went back for my first dosage in April of 2011, I was suppose to go back on July 15th of 2011 for my second dosage , but I was unable to do so due to health insurance and since I haven’t gone back just recently my nipples have became sore, but there is no sign of milk leakage what so ever. So i wanted to know what does that mean knowing that my nipples are sore but there is no milk coming from it ? and if there is a chance that i may be pregnant?