It must be so depressing to feel lonely. I spend a lot of time on my own, but am thankful that loneliness rarely bothers me. I keep busy with various activities, and try to get out of the house at least once a day. A walk in the fresh air, or even a wander around the local supermarket can lift my mood, especially if it involves buying a tasty treat!
You don't need to have your own dog as a bridge to making friends. When out walking I often have a good chat to people just by admiring THEIR dog. Only yesterday I chatted and walked around our local country park, with an elderly lady, for about an hour. She had a Shi Tzu with her. Just remarking that my daughter has two of the same breed was enough to trigger a conversation. She lives alone, and I think it did her a lot of good, too, to chat to someone.