Worried about Chloe!!!!

I know I am being over Cautious but if the cat that I was currently fostering had a cough and minimal nasal discharge. I ALWAYS only touched her and the kittens and then washed with antibatcterial hand soap and even went as far as making sure that I changed my clothes between contact is this over kill on the saftey measures???? And if not should I watch closely to make sure that my cats don't start to show signs of any kind of illness??

I am so scared I can't explain how much NOTHING can happen to my youngest or the other two adults I worry about her because she has come so far and I am so attached to her right now. She is like my bestfriend. Even if she is a cat I care for her and the other 2 cats. I don't want to expose them to anything. They NEVER had any one on one contact AT ALL. I haven't even let them in the room that the other kitty was staying in until I go and buy a germ killer at the store tomarrow. Any suggestions on how I go about making that room safe for my cats to be in?? :confused:
Thanks for any help :(