HELP👀

OKAY I TOOK DEPO FOR THE FIRST TIME IN MARCH ON THE 24th AND IT LASTED ONLY THREE MONTHS AND I NEVER WENT BACK TO GET ANOTHER SHOT WHILE ON IT I HAD BEEN BLEEDING THEN THE BLEEDING STOPPED A MONTH AGO I HAVENT HAD A PERIOD SINCE AND ME AND MY EX HAD SEX THREE DAYS AGO AND IM SPOTTING WHAT DOES THAT MEAN ?