I only got one depo shot in April I was suppose to go back July, I decided not to go, In August I got my period, and all September I missed. Is that natural or is it possible I can be pregnant. Note, I had pregnant the week before my period was suppose to start on September.

Can you re-phrase your question? I don't understand what you mean by "I had pregnant..." Do you mean that you took a pregnancy test, or you got pregnant?

It's entirely possible to simply miss a period. It takes at least a few months for your body to fully get back to normal after starting or stopping birth control.