Well, Matthew, let's say you know what not to do - staying in the house. You know that's getting you nowhere.

I was never much of a social butterfly, myself. What I find helpful is some sort of structured activity. Going to school, even just for one class, can help - though often I found that disappointing. (Classes where you learn to do something work better.) Volunteering is something I think can allow you to interact in a meaningful way. I got some nice invitations from fellow volunteers. The trick is to stick with it. If you want an instant payoff, you may be very disappointed. The local animal welfare shelter often needs help. These days agencies recruiting volunteers act like employers, wanting an application filled out with references. So you have to get past that.

I made some friends just from taking a dog to the park. We started walking our dogs together. That led to other things. Then there are "meet ups" which I haven't tried, but some say they're good.

I hope you'll try something. Nothing will change until you do something new.