Is it too late to back out of our lease?

Me, my boyfriend, and a roommate shared a apartment for a year. Our lease is up in about a month but we already signed a new one. Our roommate was the head lease holder but he isn't signing the new lease. He's moving back home with his parents. But he hasn't signed the roommate release form yet. So does that mean our lease wasn't completely finalized yet? Our apartment managers are really snobby and refuses to fix the air conditioner. It gets unbelievably hot in our apartment. And she always has an attitude with us. On top of that, they are doing construction all around us which causes the buses not to run this way anymore. I need the bus to get to school and work because my boyfriend works a lot. So my question is, is it too late to back out even though me and my boyfriend signed, roommate didn't sign, and they don't even have our income information yet? Thanks!