Depo injection

so I had my 1st depo injection on the 14th august was ment to get it re done but I didn’t go back because I completely forgot and had a lot going of.. my last period was on the 6th-12th October & period still hasn’t came back on since.

Had a few mild symptoms nipples are abit sensitive & really bad back pain

Took test but come back negative. How long will it take for my period to come back..