I am posting this here mainly for my own personal record, but anyone else is welcome to know too:
I am pretty sure Baby Boy had roseola but is over it now. He had had a slight fever (only around 99-100 degrees) off and on for a couple days last week. I didn’t think much of it, and just breastfed him a lot, and then he was fine. Then on the evening of May 1, I noticed a rash on his chest and tummy. In the morning, it was covering his front and back, on his neck, and very lightly on his face. He had no fever at all at that time and was perfectly happy, so from my research I concluded it was not measles (because he would have been acting a lot sicker and would have a high fever), but roseola. It was mostly gone yesterday (May 3), and seems to be all gone now.