Dr Byrnes got it! Vounteering is a wonderful suggestion. Once we are out of school, retired, or just not working, many of us get lonely because we are, in fact, alone. No one should be alone all the time. I suggest: joining a church, a community center, or even an aa or al-anon fellowship if appropriate. Volunteer at: a library, a soup kitchen, a volunteer ambulance, a shelter, you name it!
Volunteer. First, make friends with yourself. You're ok and you can do this. Then go volunteer to help with a worthy cause. It doesn't matter which really. Soup kitchen, public library, red cross. Ask others you meet there what their story is, then listen. Keep doing this until you run into someone who will ask and listen to your story.