I was treated for chylamdia with amiztrocyin im on birthcontrol too my cycle is supposse to start but its only dark brown discharge with little blood?

Well: Small period ok with ocp and azithromyci should knock out chlamydia quickly lest intercourse occurred with an untreated person. U need a follow up "test of cure".

Birth control: It is not unusual to skip a period or have a light period while on birth control pills especially if you are taking the 24 or 26 day active pill packs or taking active pills continuously.