J.M.
My daughter is almost 4 and has been in daycare all her life. She is a shy child and still has times where the dropoffs are terrible, crying and begging us not to leave. I always call an hour later and the daycare provider says she stops crying as soon as we leave. When I pick her up she is playing and very happy and not always ready to go home. Her dr said some kids are just like that. I have read that a new baby causes older children to regress, go back to bottles and bed wetting, so crying again at drop off is probably part of that. We do a reward chart. every good drop off gets a sticker and at the end of a week she gets a treat. We use reward charts for a lot of things and it really works for us
Good luck (I know its really hard)
J.