I'm sorry I don't have an answer for you but I can definitely say I've had a similar experience. Right after New Years last year 2012 my mom had an awful sv*, because I was so scared of catching it I spent the entire day out of the house with my then boyfriend even eating dinner out at a Panera in my town so I wouldn't have to touch anything at home.
Despite this the next day I had to leave school because I was so nauseous and wen I went to bed that night I v* twice and my fever was 102!!! I too kept asking myself how in the heck I caught it while my brother who stayed home with my mom all day only had a little d*