Jude - i know that feeling exactly. and i remember others here expressing it similarly.
i always feel like i don't belong. like i am different. like there is a big sign on my back that identifies me as a phony who is masquerading as a real guy. (notice i didn't even have the nerve to say "man.") like the others are just tolerating me and can see through me and will be glad when i leave. like i am an outcast who has deceptively infiltrated the ranks of the normals and is likely to be exposed at any moment. like i am outside myself observing how inept and what a big loser i am...
face it - we ARE different. we have experienced things that set us apart. we see things from a different perspective - and have deeper insights to some issues - and no common ground with normal guys in other areas. nobody ever taught us how to be one of the gang.
and sometimes i am glad that i am not as shallow and mindless and simplistic and as much of an instinctive animal as the way i see them. and other times i long to be just that - with no reason to have to even consider anything but the trivial stuff that occupies them.
in short - NO - you are not alone.
They have greatly oppressed me from my youth, but they have not gained the victory over me.
Plowmen have plowed my back and made their furrows long.
But the Lord is righteous; he has cut me free from the cords of the wicked.