The day has gotten much better. DS seems happier than this morning, calm, less energetic (asked to come home when we were on a walk-usually could go walking for hours), and still a little more emotional (gets sad and irritated easily). I have read that for some, these emotional side effects fade or disappear after the first few days or even weeks. I hope that's the case for my little guy. So far, he's not having any physical side effects other than a very slight dry mouth and loss of appetite. He's still eating when I give him food, but he doesn't ask for any snacks like usual.
