I think Alphagetti is right, nothing has to have changed at daycare or home and is a phase but doesn't hurt to ask them.
I had a little one do this before and the parents and I arranged for them to give hugs and kisses in the car. They walked them up to the door, I took the little one into the house and they waved good bye. Few tears for a week but then it became routine and the fits at the door stopped.
Good luck