Separation Anxiety starting?

This morning when I left DS at daycare, he was crying. :-( That's the first time that has happened. Lately he has been more reluctant to have other people hold him when he can see me. I'm sure he got over it very quickly, because he is usually very happy with any of his teachers. I handed him to one of the teachers to finish checking him in (filling out a form with when he last ate and slept), and he cried then. So I took him back when I finished and he quieted down, but I couldn't stay because I had to be somewhere across town at a specific time today, so I handed him back. Then he started to cry again, so I just kissed him and told him I would be back at lunchtime and left. I think I said, "I hate this part" to the other teacher as I closed the door.