I am exactly the same way!!! I didn't know there were so many other people out there who were the same way!!
If I hear that a friend or a family member has the stomach bug then I run the other way or I start to panic that I'm going to catch it. When the winter months come (and stomach bugs are more common)I start to worry that someone in my house is going to catch the stomach flu and give it to me.
The last time I had the stomach flu was 6 years ago and it went around my entire family...it was terrible....and it scares me that I'm going to catch it again!!