We went through a similar period when my DS started childcare, but he was quite a bit younger than your DS. I'd never left him with anyone before really, so for him it was a huge thing and he had to learn that I would always come back iykwim? Even though he was only one, he was still doing everything he could to make sure he was in my arms or having my one on one attention all the time. But that would only last a day. I made a point of saying to him all the time 'mummy always comes back'. I'd tell him that when I left him at CC and when I picked him up, but also throughout the day, like if I went into another room for minute at home and then came back.

I was really lucky cos the room leader would always call me if he was too upset (which was pretty often in the beginning) and see if I wanted to come get him. Personally, I think it is important that they do this, because if they get too upset they're likely to develop negative associations with it.

After about 3 months it all settled down. He stopped crying when I left him and when I picked him up, and then started to get excited when I told him he was going. So it does improve, it's a huge learning curve for them iykwim?

he has his blanket and teddy for nap time- but they discourage the kids from bringing their own personal toys there as it can understandable cause some fights!
The center suggested we keep a couple of family photos in their bag, so when they are upset the staff can get them out and they can hold them and feel close to you. Also things like making a point of driving by the centre when your not going and pointing it out, talking about having fun there etc.

Anyway hope this helps, good luck