I am 20 years old. i have been spotting brown for 9 days. the first 2 days it was light pink now just brown. not enough to need a panty liner or anything. my period is due in 3 days. my lower and middle back hurt alittle. more like a dull ache. im having minor cramps. my left breast is sore more around the armpit area kind of feels like its bruised but not my right one. ive also been having some headaches. ive never had stuff like this before. i normally get my period on the same day and it starts heavy with bad cramps. ive been on yaz birth control for 7 months. about 3 weeks ago i was sick and on the antibiotic z pak for 5 days and the steroid prednisone for 5 days. i have had alot of unprotected sex this month. what are reasons why this could happen? could i be pregnant or something else? please help!