our children are channeling each other!
Oh, Holly, you just posted on my thread and now I am going to post on yours.
What you described with your son is yet *another* thing that is going on with my dd. She went to pre-school last year with no problem, but this week she has been crying when I leave her. She goes by carpool, so all I can do is wave good-bye as she cries!!

I don't know if your son will find this too "babyish" but one of the babies I babysit for brings his mom's pillowcase along because it smells like mom and he can snuggle it. Well, my dd thought that was really neat, so when she started these separation anxieties, I offered her *my* pillowcase and she loved that idea. I take it off the pillow in the morning and she brings it.
I also talked to her teachers to let them know she was having this trouble (although it was quite obvious.) ANd I just tried to reassure her that she will get used to her new class. Its frustrating because she seems to have so much fun at school, so why these anxieties?
She had two days of big crying fits in the morning, and then 2 days just being a bit tearful. She doesn't go to school on Fri or Mon, so we'll see what next week is like.
My dd seems so angry lately, too. Is this normal 4/almost 5 behavior? Have other moms had this experience?