I was on the Depo shot for about 3 years

Patient: I was on the Depo shot for about 3 years. My last shot was due in September and I didn’t get it. I have not gotten a period since. I think I might be pregnant but I took a test a month ago and it was negative. I then was like okay, but now this month there is more then the month before. Now if I am its only a couple weeks but how am i to know since I don’t get a period ?How long does it take to get a period after being on the Depo? How long does it take to get pregnant ?

Symptoms: Tender in the breast, dizzy, bleeding during/after intercourse

Doctor: