freemediinfo.com/mmr.asp
Mild joint pain or stiffness for several days may occur within 1 to 3 weeks after MMR injection. This only ... .
It's great that you're going to the doctor to ask because I am very sure that I don't know and I don't have any advice.
If it makes you feel better though the homeopathic thing I heard was that a reaction like a small fever to a shot was actually a better sign in the long run because it means the body is self aware enough to respond to the shot.
About the potty training My sister she potty trained my nephew by reminding him to go potty and having him "try" on a schedule. Excuse me, but I was like, "can you 'go' on command or do you go when you need to go?". Maybe that's your son's issue with the preschool potty.
Daycare providers might think nothing of lining kids up to "try to go" on a schedule and that might be bothering your son if he's used to going when he feels the need. Alternatively, being unpotty- trained could be one less thing than he can handle right now with everything changing. My son unpotty- trained shortly when I had a new baby. He retrained several months later.
I want to be reassuring for you not to worry so much that he hated this one preschool experience so badly. His feelings may be sensitive or easily hurt compared to his age. But he will still grow and develop like a normal human being. The bad times might be less tolerable, that's all. That doesn't mean they'll be mostly bad. You can't predict the future from one bad experience. Sometimes you'll find a teacher you guys love.
