Alone and depressed

Now in my 8th decade, your message in turn may me reflect in the same vein. 

Growing up, I had an older brother who was physically disabled, so I was his arms and legs so to speak. These days I'd probably be seen as his carer, but it didn't feel like that at the time.  He passed away unexpectedly almost 50 years ago at the age of 24, and I have felt lonely and alone ever since. I know a lot of people, but have no friends or family to turn to/talk to.  I've been married for over 45 years, and can confirm that there is no lonelier place to be than in an unhappy marriage.

For years I would think to myself "Why aren't I like other people"? Although I haven't had a formal diagnosis, based on test results and life experience I'm quite certain I'm autistic as it's now viewed.  Unfortunately, when it mattered ie when I was a boy/young man, autism had a much narrower definition and indeed a stigma - certainly rarely talked about.  My struggles were not noticed, other than possibly when I was about 9 and my school report said "needs more self-confidence"; nothing ever came from that.

I'm usually OK in a one-to-one situation, but as soon as there are two or more other people I'm always the one on the outside.  I can't bear parties; the more people around me are enjoying themselves, the more withdrawn I become.

I have very few hobbies, and whilst I used to listen to music a lot it's become one of many things that just seem too much effort.