Originally Posted by
J_9
Your question is quite confusing. If you got your Depo on or around September 10, then you aren't/weren't due for another Depo until on or around December 10. So you aren't really late for another injection until about now.
You wouldn't be considered to be off Depo for a month until around January.
Considering you aren't really that late for the Depo shot, how do you know that you were ovulating on December 1? In order to know your ovulation dates you have to track your period for a minimum of 6 months using the basal body temperature (not a phone app), without being on any form of contraception whatsoever.
Since you are just about now due for another Depo shot, and you haven't had one, most likely you are experiencing break through bleeding and your body is starting to adjust to your natural hormones rather than relying on the hormones given to you artificially by the injection.
What concerns me the most is that you don't know exactly how Depo affects your body and that you don't know how to track ovulation.
If you are not wanting to get pregnant you need to refrain from sex altogether as there is no form of birth control that is 100% effective aside from abstinence or a total hysterectomy.