M.
That sounds like a stomach bug that went around my house a couple months ago. My 4 1/2 year old son would seem fine all day then wake up at midnight and puke all over his bed. This went for almost 2 weeks off and on. It started with my one year old, then the 4 1/2 y.o,, then my husband, then me, then back to 4 1/2 y.o., back to husband, back to 4 1/2 y.o. Before this my son had never thrown up before so it was just horrible! It is extremely contagious as we were very careful to wash hands, sterilize toys, doorknobs, etc but it still got passed around.