Sounds like you are going through burnout. This looks like a helpful site Lisa has given to you.

You need to get away from all of this, even if its just for a few days, otherwise you will not be doing anyone any help! Kittens are always going to be born, you have got to realize that you will not be able to help each and every one of them. You are doing the best you can, and believe me, everyone appreciates it.....even all the kittens & cats you have come across.

Take some well needed rest!