I've experienced this although I'm not fully recovered. But recovery for an emet usually just means that we don't fear vomiting to the point where it limits our lives and it's a more generalized fear, even non-emets sometimes get afraid or apprehensive upon getting sick especially with a bug, it's just natural. By bug I'm assuming you mean noro/stomach flu and in that case it could be anxiety due to part of your brain still feeling as if it needs to protect you from it. Assuming you've been an emet for years the anxiety is going to take awhile to "go away" completely (and considering most people with phobias have some type of anxiety disorder, it never really does) since you've built up a routine and way of thinking about it for years. It's going to take time and I would consider talking to your therapist (if you have one) about it, since it sounds like you might have a skewed perception of the bug that's making you anxious still.

I feel like it's common for any recovered phobic/disorder to still have a sense of anxiety about the thing, sort of like PTSD, and sometimes people are just afraid of getting better overall. But remind yourself that depersonalizing is harmless and it's just your anxiety. Breathe and ground yourself (five things you can see, four things you can feel, three things you can smell, two things you can hear, one thing you can touch), you're perfectly safe and you're gonna be okay.