Preschool Anxiety

Leo started preschool in September. It is a 2-day-per-week program, 5 hours each school day, so he isn't there often.
The first few days he did fine- and then suddenly school dropoff became crazy time. "I don't wanna go to school" is the morning refrain:
"Here, eat some breakfast- look, mommy made eggs!"
"I don't wanna go to school."
"Let's go take a bath. You can play with your bath toys..."
"I don't wanna go to school."
"Honey...can you grab his clothes while I'm drying him off..."
"I don't wanna go to school."
I'm not sure how other parents get over this. I guess it just gets better with time. Justin suggested- jokingly, of course, that we need to be meaner to him at home. We're obviously so fun to be with that he doesn't want to leave.
We've tried being enthusiastic about the toy fire trucks at school, the little playground out back, all of his friends who will be there...
We've tried promising we'll play trains when he gets done, go play in the backyard, go take a ride on the ferry (the terminal is a few blocks from home and the ferry is super-exciting when you're two.)...
Still...it's "I don't wanna go to school."

At some point, I just wanna say "Suck it up. You're going to school." But that's obviously going to be counterproductive.
So we promise and cajole and insist...
And after a teary-eyed walk to school, we hand him over to the preschool teacher and pass by the window on the other side of the classroom. By the time we make it around to that side- he's happily playing firetrucks with the other kids.
Man...I wanna go to school!