What should I do? I can't stand living with my aunt.?

I just turned 18 and graduated from hs. I going to University of Iowa in the fall but until then I am living with my aunt, her three kids, and my grandma. I am a military brat and my mom is currently stationed in Japan, so I can't go back home because the military already paid for my ticket to the U.S. I've only been back less than a week and I already can't stand it here. I love my family but I can't handle two months of this. My cousins are 4,3, and 10 months. I'm around them 24/7 because I don't have my drivers license yet and we only have one car anyway. My 3 year old cousin keeps repeating the same thing over again and again. I can't take it! I don't even have my own room. I share the loft with my grandma. I sleep on an air mattress. My grandma and I babysit the kids while my aunt works. Help!!!! If I have to deal with this for the rest of the summer, there will be a mass murder :/