I won't deny, I am massively worried about my future.
I am an only child (as is my partner). I am in my mid-late 30s, and whilst I would love a child, I don't feel it would be fair to them, as we just wouldn't be able to give the child any extended family. I think in not having children I am being selfless, rather than selfish (as some might accuse me of). I only met my partner fairly recently too, so it isn't like I have deliberately put off having children.
For those who are saying you will rely on your children in old age, please don't underestimate the pressure this will put them under, especially if they are an only child. I am just starting to experience declining health of my parents and as an only child, I feel under a huge amount of pressure (even though I don't even have to provide much support at the moment). It consumes my thoughts day and night, and I have had to start medication for anxiety and depression.
There's also the huge worry that I might find myself completely alone in the future. The thought of that is unbearable. Whilst I would never end my life, if I opt to have never existed I would.
My only hope is that I might be able to build myself a community of friends. I have a lot of hobbies and interests, and although I am a quiet kind if person, I make friends quite easily and am relatively popular at work etc. For example, have a lot of people who reach out to me each week for a chat / to see how I am etc and I reciprocate. I try to tell myself that this demonstrates that I am likeable.
I also hope that when I am older I will be able to move myself (and hopefully my partner too) to a continuous care community. You start with independent living and gradually move through levels of care as required. I have found a lovely place fairly near me. It's like a country hotel to be honest! The grounds are gorgeous and I think I would enjoy a nice peaceful time there doing things like painting and drawing, with companionship and care on hand as I need it. It's expensive, but I should be lucky enough to be able to afford it. I work hard and do my best to save money towards it.
I can't help that I have ended up in this situation and am facing a potentially lonely future, but all I can do is my best to find strategies to mitigate the problems I might face. I think some people on this thread should try to be a little more compassionate. If you have had the good fortune to have a family and be surrounded by lots of people who will happily 'look after you' in old age then please consider yourself very fortunate. But please try not to scare others who, for no fault of their own, haven't shared your good luck. Life is such a lottery. All any of us can do is enjoy the time we have, plan and prepare as best we can, and try to do some good with our time.