I need advice.

July 2014 I started depo, my husband and I decided in April that we wanted to try for a baby so I didn't get my May shot. I understand that it takes about 3-4 before it is out of your system, and it can take 1-2 years or more before you can conceive. My concern is that I haven't gotten a period yet and I have been off depo for 4 months. Should I go to the doctor? Could I be already pregnant?