(wisewoman) i am sorry for your hurt. the behavior of your co-worker is absolutely ridiculous in my opinion. it seems to me that aside from being insecure, she does not know how to handle babies. for her to take this child away from you and putting it on the floor (!) shows to me that she should not even work there. i am sorry that you feel like you can't go back to volunteer there, since you seem like a very caring person and a baby-loving one on top of that.
Good for you though for standing up for yourself like that. I admire your bravery