I sympathise with you all here because I suffer with this phobia. What you need to do is take control back for yourself. Have a read of this, it WILL help:
First & most importantly: The more you think about it, the worse it will get. I can guarantee that even people who are not emets would find themselves feeling nausea if they continually think about getting sick or think repeatedly about anything related to it.
Let me ask you this.... if someone stood in front of your scratching frantically, scratching their head, their arms, their body..... before long you'd start to feel all itchy & start scratching too. What happened is that this person's behaviour triggered the first thought in your mind about itching. Then that lead to scratching & so on. I just scratched my head because evening thinking about this is making me itch.
What happens is that simply one negative or horrible thought is leading to another and another...... YOU NEED TO BREAK THE PATTERN OF THOUGHTS. Every time it comes to mind, BREAK THE PATTERN & CHANGE THE SUBJECT IN YOUR MIND to something more healthy and pleasant.
So yes, playing computer games, listen to music, draw, write. If you're at work, get stuck into something all consuming. Whatever it is, the moment you feel the trigger - fill your mind with something other than these negative thoughts. It is recognising & changing the way you behave when you notice that initial trigger. That trigger point is when you need to act.
Before you think I'm just saying this to make you feel better - it has worked for me. For example: I used to lie in bed waiting to fall sleep & then the thoughts would begin. Like a film strip every night. Exactly the same sequence of gross things I'd seen or heard, all in relation to "you know what". That set me up brilliantly to lie there awake trawling my mind for more & more horrible things I remember happening in relation to my phobia. Adding to the burden of it all.
These days when I'm just falling asleep I have far more intersting things to fill my mind & think about now. True, substantiated real life things in my mind & not a load of fear fuelled speculation.
Of course I still have the phobia but I deal with it now as best I can. Wherever possible I dont let it dictate to me. Sometimes I cant immediately do something to distract myself, particularly if I'm in a situation where I can change my surroundings. There have been occasions when I've been in a trigger situation where I've needed to use techniques that block all my thoughts totally. If my attempts to change the subject of my thoughts dont work, then I move onto step 2: Repeat words over & over in my mind, obliterating all other thoughts. Usually I'll repeat "brick wall" over and over and over. Its just a temporary fix of course & usually if I do that for a minute or whatever is needed. Once I've been able to change my situation & I am no longer feeling triggered then I try to get on with my day in a normal way. Most often I succeed in ridding myself of the obsession & go back to usual.
I would love to guarantee to everyone that they wont get sick but as we know (and what fuels the fear) is that we know it can happen. Therefore its up to you as individuals. You need to decide for yourself that you are no longer going to let the phobia dictate to you. You can change thought patterns but its necessary for you to make that decision & take control. The more you learn to deal with the phobia the less it will have an affect on your life. But it is up to you.