I'm starting to relearn how the natural progression of a relationship is supposed to be that you are yourself and then through chemistry and common interest and effort someone becomes your friend, but that doesn't mean he stays your friend. People come together and they grow apart. You can't go rushing after people and plan every outing and look at your friendships like a job. Sure, maintaining a relationship takes effort, but it shouldn't be strenuous work. It should not be one sided. And, often, how you see your role in a friendship is completely NOT how the friend sees it. Sometimes you just grow in different directions and lose sight of each other only to come back together years later. Sometimes you think the world of a person, but at that time your life is filled with turmoil or other chaos so you never get to know that friend like you wish you did. Sometimes you've been a complete asshole and that's why no one calls you or invites you to things. You may not even be aware of what you've done, and it's really hard to ask someone what is going on when you feel disconnected from everyone.
Sometimes you look around and realize that, as you are, the world isn't very much interested right now. It doesn't mean you're a terrible person and no one wants to be around you. It doesn't mean you should cut yourself off from everything. It just means that right now, at this moment, you find yourself without a person who knowingly rolls their eyes with you, understands your private jokes, knows what to do when you need someone just to listen and not try to solve everything or make recommendations. You're without that person who fundamentally gets -- you.
And some days, I think that you're the only person that can really understand you, and although people are often wonderful (although sometimes not) additions to our lives, we still live and die alone.
But that doesn't mean you stop trying to make connections. Connections are what making life worth living. I can't imagine not getting out there and trying. Can you?