How can I fight depression in my situation?

I'm babysitting my 3 little nephews with my other sister, while their mom (my oldest sister) is working all day. I'm only free from 6 pm and the week ends. I'm kind of living with them right now, and they're really annoying, the house is always so messy, even if I clean up all the time, they're so noisy and mean...well they're kids! But it's summer and it's hot outside, and I'm 19, I want to enjoy my holidays the best I can, I just feel that I'm not free to do whatever I want, I can't even listen to music because they're so noisy! I'm so depressed and I hate that! any advice?