MY CAT IS ILL AND I NEED HELP!

Hi everyone. I have looked over recent discussions where people have called on members for help and I really need some advice. Last June I found a 1 month old kitten on the side of a highway. By the grace of God I had my window down and heard her tiny meowing off the side of the curb. She fit in the palm of my hand, and I couldn't leave her there alone. Fast forward a year- my cat has been diagnosed with a chronic rare illness where she is literally allergic to her own skin. She breaks out in rashes and constantly has chronic issues with her skin. I found her as a college student ( I am recently graduated and trying to live independently) and I have spent lots of money to work with her in order to make her comfortable and happy in my home with me and my dog Ivy. I feel horrible because I am at a point where I don't know if I am the right person to care for my cat any longer. I would never want to turn my back on any animal and I constantly catch animals on the street and send them to humane societies. I was going to do the same with my cat but I just loved her so much and thought she would be a special addition to my home and family. But I am finding it hard to care for her now and she is feral and hostile to unknown friends and especially the vet- which limits her ability to really treat her skin issues. Please help me try to get control of my home and help my cat. I don't want to give her away because I am terrified of where she may end up or how many homes she may be moved from because someone may feel as I do that her illness is too demanding and overly stressful. I need advice on keeping my home clean and sterile ( I hate that she kicks litter out of her box and tracks it around the house), I need advice on caring for an animal that will always be chronically ill, and I need advice if necessary on what further steps I can take to have her placed in a forever home where maybe someone else is more equipped to care for my cat (she is sweet and loving once she gets comfortable with you and without her sickness and messiness she would be a dream). Thanks in advance for your advice and support. I would love to keep her if possible but I need help in changing the way we are living now or else I feel I will have no other choice. Thank you.