I suffer from fear of vomiting, it cripples me and I have recently begun to recover... I have gained weight back, but I'm still awfully thin.

I had a friend over the night, we slept in seperate beds but we did hang out.
When they went home, they were fine but an hour later, they threw up. No fever or loose stools and they felt fine before and afterwards. Four hours later, they were ill again, still no fever or bowel problems.

I have washed my hands and cleaned anything they touched.... is there anything I can do to help myself not get sick?

RS

p.s. No chills or headaches, they feel fine between the two occasions.
not tired, worn out or achy.