Ds started at nursery just two mornings a week. He's 18 months old and has only been left with family before but we feel it's good for him to mix more with other children and he's such a confident little fellow I felt sure he's be ok. He's been 4 times and although I expected him to cry when we dropped him off, apparently he cries on and off the whole time he's there. Is this usual? How long will it go on for? Also do I make it worse by leaving when he's not looking, should I properly say goodbye?