I can totally relate to what you're saying. I have emetophobia too and I just stop eating when I feel full. Luckily, though, my weight is still okay, although people already tell me that I seem to lose weight. Not sure if I agree with them or not. The last time I continued to eat when I felt full, I ended up with severe anxiety until about 3-4 am in the morning, almost having fallen asleep in the bathroom next to the toilet, 'just in case'. So after that incident, I just wouldn't eat anymore if I feel full in the slightest.
I once also didn't actually know what it felt like to.. get stuff out of your system, because it just didn't happen for almost 15 years. Until I ate a cheap kebab shortly after New Year last year.
If you get sick after a meal, can you also not eat that meal anymore because you associate it with getting sick? Do you also remember every single time you got sick or anyone else got sick as if it were yesterday? I do and I just wish it would stop and I would forget.
The last time was February and knowing that it's not the end of the world still doesn't make it any better.
But I'm with a university counsellor and he was able to help me significantly! I rarely get any panic attacks now and I try to control my thoughts and steer them to a more positive way. It helps me to think "And then...?" instead of "What if...?" because it makes it clear to me that I will not die or nothing bad will really happen if I do get sick again whenever I feel awful.
My counsellor also suggested that I may have a fear of losing control/not being in control in addition to emetophobia. I can't stand not being in control of whatever: sitting in a car when I'm not driving, not being in charge of organising something, developing feelings for someone, ... It drives me nuts and makes me anxious because I often assume something will go wrong if I can't control it. Which just makes me sound like a control freak, I know.
I will go back to my counsellor when I'm back at uni. I felt so much better whenever I talked to him, but also pretty emotionally drained. I'm just glad I haven't had these bad attacks for a while that would last until the wee hours of the morning (like 4,5,6,7 am), so I assume the sessions with him have helped me!