What do I do?

I just came home from a week long vacation and left my cat to my aunt, walked into my bathroom and discovered reddish liquid in the corner the sink counter and all over the tub. I poured peroxide on it and it was blood. My cat is peeing blood so I took him to the vet they explained everything to me and I broke down crying because I cant afford the treatment hes barley going to be 1yrs old in 2 weeks. I dont know what to do and I don't want him to die. He's fine right now but if his infection gets worse I have to put in down! He got the infection because he was stressed from being alone most of the time and all I can do now is give him liquids and hope he gets better, I ordered some medicine for him but I won't get it til tomorrow.