Preschool Update

I am at my parents' house right now, and I have a limited amount of time to type before Jack comes upstairs and discovers I'm back from yoga already, so this will probably be quick.
We have now been to preschool a total of three times.  The first time... well, read the previous post to see how that went.  The second time, Jack cried when I dropped him off, but he was quite cheery when I picked him up.  The teacher said he calmed down after I left and really enjoyed his tap class in particular.  I was feeling good.  Then there was the third time, yesterday, which as any parent will remember was the dreaded, "Day After Halloween."
I tried to get Jack in bed on time after trick-or-treating, but it didn't happen.  He ended up falling asleep about forty-five minutes late - not too bad, but then he woke up at 6:30AM, an hour earlier than usual, because his pull-up had leaked and he was all wet.  There was no going back to sleep after we got that cleaned up, though I tried.  So, when I dropped him off at school at 9AM, he cried, as did several other overly tired kiddos who where being dropped off at the same time.  I stayed strong, gave him a kiss and a smile as I left and worried most of time I was gone.  When I went to pick him up, they were on the playground, and Jack was crying in the teacher's lap.  It turns out, he had calmed down after I left and had really enjoyed painting and tumbling, but he had gotten the mistaken impression I was picking him up before lunch.  This is what caused the meltdown about forty minutes before I got there.  I had explained to him when I was picking him up, but it didn't sink in, apparently.  It was good to know he had enjoyed at least some of his time there, but as a parent, it's pretty disheartening to drop your kid off crying and then pick him up in the same state.
I am blaming this backslide at least partially on Halloween.  I'll take him again tomorrow and hope for a better day.  I'll also try to do a more thorough job of explaining when I'll be picking him up.  *Sigh*  This preschool thing is hard, but I'm hoping in a month or so I'll also add, "but totally worth it."