burdsinflite - I know how awful it is.

For me, it's fear of perpetual loneliness.

For you, I think it is very significant that you mention that a relationship, that I think you would like to keep going, may be ending.

My significant other is in failing health and I envision losing him in the not too distant future. My family of origin really doesn't bother much with me. (I moved thousands of miles away from them, so I kind of understand.) I have no children. I feel like if I were to get sick, or in some other kind of bad jam, I would have no backup . . . no network of support. I would be alone and dependent on strangers. I can see me ending up in my "Golden Years" as a person who is not really cared about by anyone in particular.

Like you, I can get to feeling okay, if I am in company of others and sharing some human warmth.

Human Beings evolved to live in family tribes, spending their whole lives always close to a clan of relatives with whom they were intricately involved. We modern humans scatter ourselves around and lose those ties. We move. Our relatives and friends move. Everyone focuses mainly on their immediate nuclear family, and the sense of extended family can get completely obliterated for some people. I have 3 siblings. None of us hardly ever talk to each other.