Tracy you have certainly not failed! You have done a wonderful thing by rescuing the cats in the first place, without you they wouldn't have had a chance for a good life in the future.
Taking them to a shelter than can cope is better on yourself and the kittens, and maybe when they get better you can take some of the back.
But you have to make sure your own environment is safe and clean and ringworm free before you can help other cats, after all if you're in a state of stress you will not be able to help the cats. You have to put yourself first get your own cat sorted out and then when everything has a clean bill of health then you can start your wonderful work again.
I'm sure they'll all find loving homes from the shelter, and you've done a wonderful thing in helping them with a good start to life.
The ringworm was unfortunate but certainly not your fault and 17 ill cats is a lot for one person to deal with!
You're a star, and a great person for helping cats in the first place, after all there are so many useless losers in the world who just think about themselvs and nothing else, you're one of the great ones
As you can tell from the posts everybody supports you in what you do and we are all here to help