Getting pregnant after depo

Hi im new to this group! I have a 2 year old son. I have been in a stable relationship for the past 4 years with my son's father. We are wanting to have another baby and i desperatley need advice on getting pregnant after being on the depo shot. As soon as i had my son i was on the implant for about 2 years, after that I was on the shot for about 3 months and it should have ended in feb. we have been actively trying for a few months now and im curious how long it took some of you to get pregnant after getting off of depo. my periods have just become regular a couple months ago (this has been the first time since i have been pregnant with my son that i've had regular periods) and how am i sure im ovulating??