I don't want to stress you out more, but she absolutely should NOT have said that. You should hold and cuddle and play with your son as much as you want, and if she doens't believe that, then you want a new daycare situation.
He is a little baby, you can't spoil them. On your behalf, I am furious she said that!! Picking your child up is a way of making them feel secure. She apparently doesn't value that. The more you pick him up in a timely way, the better he will learn to cope when he can't be picked up.
The truth of daycare is because of the ratio of kids to adults, the provider will be less responsive than a mother. That is daycare. However, she should be working her @#!?@ off to do simulate the home environment.
Excuse the language, but it makes me very angry and brings back bad memories. I started my first daughter in a daycare facility around 12 weeks. She was there for about 6 months, and I know she was safe and the staff was caring. BUT I didn't feel like they responded to her like I did. And I let it go, because I was a new mom and I was stressed out about working, etc. etc. After about 6 months, I took her out and found a situation I liked better. Same ratio, but they seemed to have genuine affection and warmth for my child. It made all the difference. And I was better about being assertive and telling them what my expectations were for my child.
I suggest you look for a new situation, and consider one where the kids are all infants. It sounds counterintuitive since infants demand so much attention. But I guarentee that a whiney 4 year old is getting the brunt of the attention at the current daycare (I have a 4 year old and a 12 week old now). Your baby just sits in a crib, so there is no pressure for her to give him the attention he needs.
I don't intend to make you feel bad. I am sure you child is safe and cared for. But I would get busy looking for something else. Your gut will tell you if it's right. And be assertive. You are a new mom, but you know what your child needs. She may be a mom and a grandmother and have run daycare for 100 kids, but she is dead WRONG on this issue. She is not the boss of your son, but I know that sometimes these women can make you feel like they know best. They usually don't.
Feel free to e-mail me if you want some support or ideas (I'm in Ashburn). I know starting back to work can be tough.