Supa,
I understand your fears and concerns. I have two boys and since boys are reportedly 4 times more susceptible, I watch them very closely. Now that my first is 4yo I feel a lot more at ease...but the younger is about to turn 2 and we had a scary time when he was 1yo.
If you google "asd video glossary" you will find a link to a bunch of videos of children (non-ASD vs. suspected-ASD) and I found that very helpful.
Also, you should be looking at the checklist for 9 and 12 months. The site asks not to repost the list but here's the link:
Hallmark Developmental Milestones
For our youngest, at 12 months he was not using any gestures, did not play with toys in an age-appropriate manner (threw everything), was not babbling, did not give eye contact (actively avoided it, in fact) and often did not respond to his name being called. Needless to say I was scared to death!
A few things happened between 12 and 14 months (we really concentrated on one-on-one time with him...we went on vacation for a week...he spent a few nights in the hospital with a really nasty cough) but at 14-15 months, almost overnight it seemed, he "awoke" into the most engaging little fella. I no longer worry about him as much (even though he is probably a bit behind the "average"...he is almost 20 months and still just babbling other than saying family names, "ball," and mimicking animal noises)...he understands EVERYTHING, even complex commands/questions, and he plays appropriately, loves to cuddle and give eye contact, has appropriate social interactions with kids and adults, etc.
So I just wanted to give you perspective from someone who's been worried about the same thing. (And by the way, I have definitely spread out his shots because my oldest got very sick after his first MMR and has a fever disorder now - PFAPA - which I believe might be linked, as they have no idea what is causing its onset since the mid-80's). Look for the possible red flags and have him evaluated, talk to his ped. about your concerns because they know what to look for. As with everything, the earlier you catch it the more you can do!
Cate