My son may have autism

So my son is 3 I picked him up from nursery yesterday that told us his hands flapping isn't normal for a child his age and he doesn't play with other children so iam worried he smart with his number and sounds but his speech is delayed witch we are all going to work together on he is also really fussy with wet food he won't touch it when offered and has started chewing his tops I have to put a cloth bib on him to stop him chewing dose this sound like he has autism? What can I do to help him ? Any advice would be great he my only child and I can't stop worrying I got some flash cards for him and he has his 3 years check up next week with the health visitor