You're not worthless, dude. For whatever reason, he doesn't want to be with you anymore. Fine. Breakups happen, though they suck. You are not worthless. You are a good person with much to offer the world, and if he doesn't love that, then whatever. Sucks for him.
However, you took a big risk and moved away from something more stable, and I think that this guy owes you a serious discussion and a bloody APOLOGY on this matter. It's one thing to end it with a partner by way of letter, it's another thing entirely if you -live- with that person and had them come to YOU. He owes you respect and help in finding out what you're going to do now.
Give your cat a hug, take a deep breath, and remember that we're all here for you, man.