I feel like that when I can't find anything I like to do. When I have a fun hobby, being alone doing it doesn't feel lonely. There's a difference between being alone and feeling lonely. I do feel lonely, a lot, since my husband left. Sometimes though, I find myself enjoying the aloneness. I get to do what I want, when I want and just end up enjoying myself. Sometimes, I feel hopelessly alone and unable to make friends or stay in touch with the ones I used to have. I was a social butterfly before I started dating my husband. Now that he's gone, I'm having to learn all over again how to interact and socialize. It's not an easy thing since I have social anxiety too. I either act like an idiot, over-compensating for my feelings of inadequacy or I hide in a corner under a dark cloud so everyone will avoid me. It's a catch 22. I understand how painful it is, believe me and I'm sorry you feel so alone. I wish I could help. You said that you can't even talk to people online anymore but you did very well here and you got replies so just keep talking. I'm here and I'm listening.
hugs
tina

Did ya ever think, maybe, that you're not the one who's crazy?