Social interaction difficulties

[firemonkey]

I am looking for something to explain the social side of things as I don't think the mental illness fully explains that.
I have always had poor social functioning and difficulty interacting with others from a very young age. In 60 years I can count my friends on one hand. I had one friend for a few years before developing a mental illness ,but lost him when I went from prep to public school, whereas for many people they have a better social network before mental illness but may lose it when they become mentally ill in their mid/late teens or older.
The only real friend I had since developing my mental illness was my wife. The relationship happened by kismet/fate rather than any conscious effort at a courtship ritual/pulling the bird (to put it crudely)on my part. I wouldn't know now how to form a platonic or even deeper relationship.

A subtle pointer to the development of full blown severe mental illness or a sign that something like ASD(traits) may be going on or additional to the SMI?
Some people with SMI have ok/good premorbid functioning while other's don't.

As far back as I can remember I have had social interaction difficulties ie long before the paranoia and social anxiety.

I don't really know how to form relationships be they acquaintances or at a deeper level friends. The whole process is a mystery to me. I expect people to react in a negative fashion towards me because I don't know the unwritten rules of the interaction game.
Some might say I am socially odd as well as being socially awkward and both make you targets for cruel minded people.

[firemonkey]

My SA is as bad as ever but the social difficulties preceded the SA by a good number of years.