Yesterday I met an old friend

Yesterday I was going for a walk when suddenly somebody told me - "You look familiar".
I can't believe it ! You are Paul ! I had not seen Paul since high school, when we were eighteen.
We were talking for a long time. I told him about my life, that I have lived in this town for ten years, and I've been very happy with my family and my work.
But Paul told me that he had had a worse life than me. I felt bad. He is divorced and unemployed. Poor Paul.
He moved to my town last month. I told him to keep in touch because I have a lot of friends, and maybe they can find him a job. My wife has lots of female friends and someone could be interested in a date with him.
Paul, I said to him, you must change your life and I'm going to help you.
Paul thought he was lucky.
Regards.

Instead of using the verb "to tell" in the first sentence, you might use something a bit less formal.

when suddenly someone called out to me (Paul called out to me on the street).  If you want to sound super authentic American you could use the phrase: when suddenly someone flagged me down (Paul flagged me down on the street.) It is an idiom the comes from the idea of using flags to land planes on a runway.