I took 1g of azithromycin with my boyfriend 3 weeks ago. at the same time, sustained from sex for 9 days. we should be clear right? today marks 3 weeks and i had white discharge and freaked out.

Details matter: Whether or not a person cleared his or her infection depends on the microbe causing the infection, the absorption of the antimicrobial from the person's gut, the resistance pattern of the microbe, the infection-fighting powers of the person's immune system, and of course luck. Different people are different, meaning 2 people taking the same dose for the same microbe may not get the same outcome.

Probably OK, but...: Presumably chlamydia, right? Or NGU? Cervicitis? Or gonorrhea? Whichever, having sex together in the first week after treatment wasn't a great idea: azithromycin is good but not perfect, and if it failed in one of you, then both would require re-treatment. Probably all will be fine, but your discharge needs professional evaluate; and you both should be retested for gonorrhea and chlamydia.