Hi and thanks for using the forum.
It can take some time after coming off the Depo shot for your periods to become regular (it is possible that you may not even be ovulating yet). The pill should help things along but it looks like it has only been about a month or so since you came off the shot. It can take up to 6 months for things to get back to normal. If you are very concerned, you can contact your OB/GYN and make an appointment. Good luck.