Hello OP,
OP, I think you sound depressed because you cannot focus on new hobbies. I really hope you can manage some walks as the change of scenery is good for you brain and nature is a gift to us all.
I think a lot of us solitary/lonely people are quite invisible to the world.
People move cities, divorce, lose family members or have families that they don't want contact with, and end up alone. That's my situation.
I have got so used to being alone I actually went on holiday overseas last year. I did love my holiday and it was worth it to brazen it out as a solitary diner at expensive restaurants. I decided I can't wait to have someone in my life to go with or I may never go. I was hoping to go away again this summer, but, well, you know...
And although I feel I have become a very strong person something happened the other day that was upsetting.
I was booking an elective surgery and forgot I would need someone to pick me up after!! The surgery coordinator said who is going to wait for you and take you home? I hadn't thought about it. I said I was planning to take an Uber. She actually laughed. I think she thought I was joking. I lied and said my son will be there but I don't think he will be able to take time off work as it's a new job.
I don't actually have even one person I could ask to do this. Before lock down I started going to a couple group things because I know logically I need to expand my horizons, but then they shut down.
I am not sure what to do about the surgery. I might just tell them on Monday that I don't have anyone. I don't think this ever happens to them because the coordinator did laugh at first, so it would seem no one else ever said that before? 
I think I will call them tomorrow and just brazen it out and see if they have any suggestions or not. I am getting sick of places that require you to have someone else, frankly.