Stopping BC of any form (pill or shot) can royally screw up your system, and sometimes it takes a while for your body to figure things out and reorganize itself to get back to normal. Like Sweet said, stress can REALLY throw your body off...some women get their period earlier and heavier than normal from stress, and some just don't get it at all. If you haven't taken a HPT since May, I'd take one again now just to be sure, and if it's negative, go see your doctor and see what he/she has to say about it. GL!