I've name changed for this 
DC is 18 months now and seems to be getting more and more quirky as time goes by, although naturally I just thought he was a normal toddler, which I'm hopeful he still is.
He hand flaps daily which struck me as a little unusual, but then I thought nothing of it, until a relative mentioned if he was saying more now.
He isn't, he can say 'Mama' and occasionally 'Ta' but that's it. He doesn't use either daily, really. Although mama is more frequently used.
He goes through periods of saying absolutely nothing for days, including not any babbles.
He also doesn't engage by looking into my eyes. It is actually really hard work to get him to look at me. If he is in the pram and can't avoid my gaze if I position myself at a certain angle, he gets really pissed off. He doesn't 'look' at people in the face really.
He also has selective hearing, and often just ignores me saying his name. It's like he hasn't heard a thing, but DH is reassuring me he just doesn't care and wants to get on with his own business.
Which leads me on to the final thing, social interaction. 3 days a week he is with other young children and he won't play or share, nor will he interact with you or include you in his play. There is no eye contact or sharing of 'smiles' at his enjoyment of a toy. He likes to be alone when playing and won't engage with children of a similar age. Is this still normal at 18 months? I read a few times from a few sources that as young as 12 months, children should show signs of social interaction. There is also no repeating of actions, for example he won't poke out his tongue and act silly if I do it, but I'm not sure if that's normal or not since he is still very young.
Someone who's child is diagnosed with mild autism said the first sign for her was when a friend came over and she played with the friends 9 month old. She said she suddenly realised she was getting something she'd never had from her own toddler - Interaction and response, real enjoyment through physical and play contact.
As a mum, I personally feel no real connection through social interaction or play. It just seems to be missing for me. I don't think I'm depressed at all! Quite the opposite. I know some might automatically assume I might have PND and detachment. I don't believe I do, I just seem to very rationally be seeing there's something missing. But despite my efforts, I just think it isn't really normal, is it?
Any advice or personal expertise would be great. I would like to ask my GP but I worry I'll be laughed out the shop since he's still a very young child.