Getting off depo

So I was suppose to get another injection of the depo shot Oct 25 and that's with the week of safety. I haven't gotten my period yet but I've been spotting off and on. I went to my doc to ask her if I can get pregnant since I'm spotting and she said yes bit it still might take a while. I took an ovulation test randomly and it said I was ovulating. My question is, did anyone else have this? If so how long did it take to get pregnant? We are trying to get pregnant with our second child.