I'm thinking of things that I was worried about as a child
What is it that you're thinking of from your childhood?
I was always lonely and I didn't have any friends.
Your childhood was a long time ago and while you were lonely then, it has nothing to do with your life today. Let go of the past and live now in the present.
But I am lonely and I don't have any friends. I'm worried that I'm going to stay like this for the rest of my life.
If you're lonely and don't have friends, you should do something to change that. Join a club or take a class. It's hard to meet people but you can do it.