You said you "can't shake thIS feeling that I'm looking at a very lonely future".
What do you mean? Do you think a child will look after you in your later years? Or introduce you to new friends/social experiences? There is no guarantee of that. My parents told me regularly that I was expected to be their retirement plan, well....I havent spoken to them in many years.
Where you say you feel excluded from most social events? Are your friends all parents of young kids? I can promise you, as someone e whoenjoyed an active social life with varied interests, kids change EVERYTHING. And organising play dates with other mums is not necessarily the ultimate social experience. BUT if you want to be involved in your friends lives more, you could always offer to babysit, or suggest lunch after a kid friendly trip maybe? Perhaps "hey (friends) I saw this (fun event) for kids advertised that looks really interesting, do you think kids would enjoy, shall we all go together and get lunch after, would be great to catch up with you"
Don't forget that the idea of being a parent is VERY different to being a parent.
I'd concentrate on finding meaning and connection to people in your life now rather than pursuing the idea that having a child would make you feel better.
Babies aren't Prozac . I dont mean that harshly. The media portray kids as happy, fun, making family memories, creating traditions etc. But for many it's exhausting, sleep deprived, expensive, no peace, if your kid has additional needs or complex issues it's an entirely different kettle of fish.
So what exactly abouthaving a kid is attractive to you? What causes you to feel pain about not having them? Having a look at your goals might help you reevaluate your options?
Fordisclosure sake,I'm an older mum, my DD is adopted and has ASD plus other additional needs.
I hope you can find some peace with this situation and wish you well for the future x