awww, jess.
first off, give it a little more time. everyone gets really really frustrated with their house at some point. no sorority is smooth sailing all the time.
what are your house rules on noise? do you have a copy of your house rules and quiet hours? ours are very well-defined. look into your house rules as well as the by-laws and see what you can determine from them. doesn't your house have common areas where noise is allowed?
overall, i'm pretty surprised you would be disciplined for this. it seems this is the kind of thing where your neighbors could just come over and tell you to quiet down, and THEN if you didn't respect that, maybe it would be time for a chat with standards. for example my next door neighbor is an accounting major, like first in her class, and is interviewing with all these huge firms. she's spending all of next week in new york plus keeping up with her classes.

well sometimes me and my sophomore slacker friends listen to the music a bit too loud, but she comes over and we quiet down immediately and move the party elsewhere, like to the tv room on the first floor. that's a spot that won't disturb anyone trying to study. (heck, that's why we HAVE a study). i dunno. it seems like maybe your chapter needs to clarify or improve your house rules so everyone understands them and can comply.
anyway, i hope you get to feeling better. i know you're stressed! give it a little time--at least through pledgeship next semester and if you're still unhappy after trying to resolve the difficulties, then you can think about deactivating.