[on]How to help my kid?

My son started day care at 9 months old. Now he is 4 years old and transitioning to a new day care colocated with school. He loved his initial day care from age 9 months to 4 yr old and made very good friends but unfortunately none of his friends are attending the same school as him. School will start in september but he moved to this new day care in school building starting 1 Aug. Over the last 2 weeks, he hasnt even talked to any other friend. When i asked him how his day was, he would get irritated and then today he told me, i went to other kids to ask to play with them and they said "go Away". This is very disheartening for me to know. How can i help my kid when other kids wont play with him?

PS: We are in downtown Toronto,