Autism

Hi there, my son is 3 years of age and does not no volume control he is the same pitch day in day out and wondering if this is a sign of autism, he also does things like when where shopping if it's bust even a little bit he goes into a big screaming fit and we have too leave, he can barely talk also hates playing with anyone he would rather sit and play by himself, he won't play with his toys just plays with his 10 month old brothers noisy /light up toys  I've spoken to health visiters, gp they are saying it's separation anxiety but I know deep down it's not that, he won't be tested till hes 5, my hv has referred him to a pediatrician to see if there's any thing there  but that takes 12 months for an appointment  he co'stantly licks his hand or has to have something in his mouth  can anyone help me, does this sound like an autistic child? Thankyou xxx