WOW. You are doing SO much better than a lot of people with this phobia and that is something to be SUPER proud of. I am picking my major right now after finishing all of my gen-eds and I can tell you there are several things I would like to do as a career but the little voice inside my head likes to tell me, "there's a high chance you'll be around sick people and then get sick yourself if you do that!" The fact that you're able to rise above that and do something your passionate about that puts you in a position that compromises your phobia speaks volumes to the kind of person you are and the person you are capable of becoming. I would HIGHLY suggest you seek out a therapist who specializes in CBT. I honestly believe that it won't take you that long to really overcome this phobia based on where you are right now. You've really inspired me to look at these possible majors without thinking about my phobia - now let's hope I can maintain that long enough to make a choice!