What to do when you feel depressed because you're lonely? (No jokes please)

Hobbies! I started back up sending letters to pen-pals. I have 15 now. It’s fun. I also go to an exercise class every week with ladies my age. I’m involved in the Buy Nothing Project and started up three groups in my city many years ago. My sister volunteers at a nursing home reading to seniors and used to foster cats. Try volunteering! I have a friend who is learning to sew and is making a wardrobe for herself from local organic material because she refuses to buy clothes that potentially were made by kids in sweatshops