Missed period help.

[user1479988429]

Hi Everyone,
I'm pretty new to this so not entirely sure what thread to post this on.
I had a laparoscopy done on the 7th June and on the same day got given the depo shot which would have taken me up until the start of September. I haven't had a period since coming off the shot and I only had the 1 so haven't been on it a while. I had my ds 21 sept 2015 and my periods returned within 3 weeks even while breastfeeding. My periods have never been off or late ever. I was just wondering if anyone has any experience or knowledge on it. I haven't taken a test yet as in trying to rationally explain the missing period so I don't get my hopes up to much.
Thanks