L.K.
Hi V.,
This is a tough call, because my first instinct would also be to go to him and comfort him. When I had to leave my son at daycare after a year of being home with him, I talked to him in detail every night about what we'd be doing the next morning. I would play with him for about 5 minutes or so when dropping him off, then tell him "I have to go to my office in one more minute". We had a ritual when we said good-bye, which was helpful to him, but that may have just been his OCD. I don't know if you already do all of this, but thought I'd pass it along in case you found it helpful. Keep in mind that this isn't damaging him. He does have happy moments during the day that you don't see. I hope things get easier for you!
L.