I'm not sure if anyone has mentioned this, but have you ever checked out meetup.com? It's basically a site where you can find out what kind of clubs/groups are in your area. There might be one for nature photography near you that you could join. If not, you could always make one. You could also check craigslist. There's a section for community activities. There might be something on there to spark your interest.

I totally understand what you're saying about self-esteem. I think it kind of works both ways... a catch-22, if you will. In some ways, you need to have some self-esteem and self confidence in order to gain friends. But at the same time, it's really hard to feel good about yourself when you're alone. I think it's a vicious cycle. On the one hand, you believe no one will ever care about you so you don't believe it when they do. But at the same time, how can you believe someone will care about you when you're feeling so alone?

The only other thing I can think of is maybe there are some coffee shops or local art galleries that would be interested in show casing some of your photographs (they're pretty amazing, btw). Maybe even a public library or an online photo journal? Getting your photography out there might be a way to opening doors of interaction with people on a more long term basis.

I'm not sure if any of these ideas were helpful, but I really feel for you and wish there was more I could do. Please keep us updated; we're all rooting for you!