DS had it when he was about 18 months. It really wasn't a big deal, but I think he had a relatively minor case. He did have a runny nose and mild fever the week before, but again very mild, not enough to take him to the doctors. Then we got the rash, which looked awful but didn't bother him. It was at this stage that I took him to the GP and he was diagnosed with roseola.

From memory, once the rash comes out they are no longer contagious and by that point the other symptoms are gone. So I wouldn't worry about going away next week, unless of course other members of the family come down with it. And I doubt that the vomiting bug you've all had is related. FWIW I understand that the vomiting etc with roseola is very rare, it's usually just a pretty mild bug which is more of an inconvenience than anything else. HTH