My first thought is that you have a lot going on right now and he may be responding to all the changes.
My second thought is that your son simply may not be a morning person and needs a bit of time to wake up. Perhaps that coincides with arriving at daycare. If you are able to organize everything the night before so all you have to do is get yourself and your son dressed and fed in the morning that might give you an opportunity to give him some extra TLC before going off to daycare, making you both feel better about the morning.
My third thought is that my SIL's and I often talk about something we call "the mom factor". We have noticed that when our children are left in the care of someone else (including their fathers) they can be pleasant, healthy and charming. As soon as we enter the picture they can become irritable, sickly/injured, clingy. It's as if they save all the "bad stuff" they are feeling/experiencing for the person who they trust the most to help them through it. Before we realized that all of our children exhibit this same behavior, it was really frustrating for each of us. Now that we see this behavior isn't unique to our own households, we look at it as a badge of honor and, though it is still frustrating, we deal with our kids more tenderly. Good luck finding something that works for you.