period MIA for 4 months? HELP

happy

okay so my last period was in the first week of may, and it was a normal period, lasted about 8 days (not abnormal for me) and i haven’t had one since. i get all the symptoms , the headaches, tender nipples and breasts, tired all the time, bad break outs but no period comes. i’m 100% not pregnant but i’m not sure what else it could be :/ i was taking birth control up until march, i’m not sure if that might have me messed up