I think mommadooo3 is right, sounds like fifth's disease. If the baby has been around anyone who is pregnant, though, you might want to tell them so they can tell their doctor.
I don't believe he has been around anyone. He was really sick this past weekend. Throwing up, and diarreaha. The throwing up has passed now, but he's still going strong at the other end:)
Very crabby too.
Becky