Hello,
Thanks for joining me on ehealthforum.
Why were you prescribed the depo shots? Was it to regularise periods or for birth control?
Discuss about your plan for pregnancy with your gynecologist/doctor and proceed with further examination and investigations to see why you are not having regular periods.
Once your periods come back to normal, that is when you start having ovulation again, you can plan your pregnancy. Before that make sure that there are no other underlying serious causes for your irregular periods.
All the best.