DS is 13 months, I know that's still extremely young but I can't shake the feeling that something is a bit different about him. My worries are compounded by DP's older child having been confirmed as ASD and DP is most definitely on the spectrum albeit undiagnosed.
DS doesn't respond to his name being called, even if I get down to his height and say his name repeatedly he'll look straight past me and won't make eye contact, just try to squirm away. He's obsessed with the wheels on his toy cars and will sit spinning them for ages but doesn't actually play with them. He doesn't wave and doesn't clap, he doesn't point. He's not very affectionate and hates being held and cuddled. He never sits still to interact with us, he just wants to be left to his own devices.
His hearing is fine by the way, there doesn't appear to be anything wrong with his hearing at all. If he hears a theme tune from the other room he'll come straight in and go to the tv.
He hasn't started talking yet, the only 'words' he says is "mmmummum" but only the noise, he doesn't associate it to me. He did say "dadadadad" for a week or so but hasn't since.
Some reaasuring signs would be that he likes playing boo when he's in the mood, and laughs and runs when me and DP pretend to hide and chase him. He's walking well, feeding himself well, sleeping well.
I spend hours every day trying to interact with him and teach him words, objects etc but he has absolutely no interest in me at all 
AIBU to be worrying about this so early on?