You asked if anyone else had felt like this. I felt exactly the same. Right down to being irrationally scared of autism even before I was even pregnant with ds. I remember when I was pg with him and was talking to someone about the 12-week tests for abnormalities, and saying I wasn't worried about things like downs syndrome, but it was autism I wouldn't be able to cope with
Like you, I thought it was the one, single condition that I was most scared of, that I could never cope with, for exactly the reasons you say - after all, being able to communicate is what makes us human isn't it 
I feel no inclination to try to move mountains to make things work as well as possible for DS in the face of this as I would if he had any other kind of difficulty
This is the key thing imo.
I think the closest I have come to coming to terms with ds's autism has been through doing something to help him, and to address the impairments he has (we started ABA just before he was dx). I thought that autism meant a child locked in a silent world forever. The day I discovered that you can actually do stuff to help really was an epiphany moment - it meant that 1) ds was actually learning and changing, and 2) it gave me something to work on, something to do, a target to aim for.
If I hadn't have realised it was possible to move mountains, I would still feel that autism was the worst thing in the world. Realising that it is possible to move mountains to help has not only helped ds, but it has made me see that autism isn't actually that bad.
Not saying it's not absolutely devastating to realise your child has it (I was in massive denial for ages), and I still have some real stuff to deal with about bitterness, jealousy, and sadness about nt families). But I have realised it doesn't mean a person with autism is actually a different species to the rest of us.
But autism does not mean a child can't learn the things you mention - it just has to be taught in a different way. Theory of mind won't come naturally to your ds but he can learn it. As Torchlight said, asd is a developmental disorder/delay - it doesn't mean a person with it is not human.
Your feelings are imo perfectly understandable.