I just want you to know that you're not alone, and I understand your fears/concerns. I work as an Occupational Therapist in a hospital! I am exposed to EVERYTHING, including c-diff, MRSA, etc. I just take universal precautions. I gown, glove, and mask when entering a patient's room with these diagnoses. (We have to anyway.) For all others, I wash my hands all of the time. I also carry an anti-bacterial hand gel with me. When I get home, I immediately take a shower.
As far as when I'm just "out and about," I make sure to turn the other way if someone coughs, never touch my face with my hands when in public, and use hand sanitizer until I get home and can wash my hands well.