Dori, I am sorry you are feeling this way. I recall we were born not too far apart and I think we have some of the same chart signatures. I adopted a dog and cat during a very tough period of my life and they have been such wonderful companions. There were times when I had nobody but them. It wasn't always easy as I moved around a ton during that time too, but I managed to find apartments or Airbnb's who would allow pets and it worked out. They are the best.
Have you read much about morning light? I go running with my dogs around sunrise almost every day and it has helped my overall health. Even being outside for just a few minutes for morning light is encouraged. If you can fit it into your schedule, it is worth giving it a try. Hang in there.
About the morning light, I gave my husband a light for SAD - seasonal affective disorder. I read about the lights from Elsa on her blog. He uses it in the morning during the 6 months of late morning light. It helps.
I am very lonely right now. I’m pretty much perpetually lonely but it’s pretty acute right now.