I wonder if I will alone and lonely at the end of life - who will be there for me?
You do realize that having kids is no guarantee that they will even be there for you when you are old. Sometimes kids die before parents. Sometimes no matter how good a parent you were they don't turn out the way you expect and won't have anything to do with you.
If that is your fear you need to start forming meaningful and lasting relationships with people. They don't have to be family. Get a group of friends if you don't have some already. Get to know your neighbors. "Adopt" a friend's kid or get close to nieces and nephews if you have any. Be active in your community.
I have an uncle who is 92 and he and his wife never had kids (wife died several years ago) but his neighbor checks on him regularly and goes grocery shopping for him, cooks and brings him food occasionally.
He has a younger brother in the area, in laws, nieces and nephews that will check on him and take him places. He still drives but not often. I went to visit him a few months ago and I was surprised by one of my cousins that was also there visiting with him.
For a person who never had kids he still has many people who care about him and is there for him if he needs. It also helps we have a huge family and his wife had lots of siblings as well.
If you don't have a large family you have to find other ways of maintaining relationships. Volunteer to help others, be a good and caring friend. When you live a good life and do good for others you will get it back.
Reminds me of another aunt who died a few years ago. She was a huge busy body and gossip but in a good way. She was a friend to everyone. She was the first to call or stop by to visit people in hospitals, bring food for sick friends and they did the same for her. When she was in the hospital there were so many people in the room and visiting all the time the doctors had to kick people out.
When she died there were so many people at her funeral the procession of cars stretched for miles. She did have kids but even if she didn't that was the kind of person she was and regardless people would still have treated her the same. She was very active in her church and other organizations so she still had an active life even in her 80's.