school sucks and so do ROOMMATES

So this is my second week of classes and I'm already bombarded with homework, papers and quizzes. It's times like this where I'm thankful I'm organized and a 'to-do' list type of person. If i didn't have a planner, I would be lost.

I can deal with school work in a timely manner, but I cannot deal with a rude, inconsiderate roommate. I live with 2 other girls. Both lived with me on campus last year, so we decided to all room together this year. BAD IDEA! Warning! It's not a good idea to move in with someone you've only known for 4 months. Ranting time. On Friday night I invited my sister and her 3 girlfriends to come to the city and sleep over. My roommates both knew I was having them sleepover. The girls didn't mind on sleeping on the couches we had. So we went out for dinner and ice cream (yes, ice cream in the winter is the best time to have ice cream) and came home to just sit and watch TV. My one roommate, KG, joined us after work. My other roommate, KP, wasn't home, so I assumed she was out. (Side note: Before we went out to dinner, KP texted me from her room asking if one of my sister's friends could let her borrow their fake ID's. I told her I'd let her know even though I was against it because she had previously gotten 3 id's taken away from her)

Anyways, my sister's two out of three friends went home at midnight. So me, my sister and her best friend all go to sleep. My sister slept in my bed and her best friend slept on the futon in the living room, which is all a big open space with the kitchen. I get abruptly awakened at 2:45 AM! to the sound of my roommate, KP, and her two girlfriends. They were so loud, I only assumed they had been drinking. I let it slide for 10 minutes, thinking they would go into her OWN room and shut the door so my sister's best friend could sleep (which she is clearly visible on the futon). But I was WAY wrong! I texted my sister's friend and told her to come into my room and sleep in here with my sister and I. At about 3:30 my other roommate, KG, went out and asked them to be quiet. They said "ok," snickered and just kept on talking. She then texted them about an HOUR and a HALF later asking them once again to go into KP room or to talk a lot quieter. They finally did at about 4:45 AM! I was furious. The next morning we got up to go have breakfast with My Dad. I was so pissed at KP, I made it a point to be extra loud in the morning, because I knew we were waking up earlier than KP and her friends were. I'm not a confrontational person, so this was a difficult situation for me. I also made it a point to talk to her when I got home, but she was not. When she did get home she did not say ONE word to me. So I haven't talked to her since Friday and I want some advice on what to do.

I don't like living with someone who I'm at ends with nonetheless not talking to. What would you do in this situation? I want it to make it a point that I'm mad at her and that what she did on Friday was so disrespectful and rude, but how? Any advice?