I only wash my hands after I shit, and if Im going to be eating a meal with my hands as opposed to using a utensil of some sort. Other than that, dont ever use hand sanitizer. I believe its overkill and unnecessary.
I know why I got sick, raged way too hard on NYE, fucked up my sleep schedule pretty bad, hung out with people that were sick and ended up smoking a few cigarettes after not having any for last few months. A series of not the smartest decisions, but, so it goes.