Cailin, be sure that you'll find people here that really DO know how you feel. And you can vent and exchange thoughts with us.
Remember that even though it's annoying when people with trivial issues (at least, they're trivial issues to us) are trying to understand. They're doing their best.
I definitely understand feeling so sad, distraught and hopeless that living seems unbearable. Not knowing why I wake up like this, with no warning, is the worst! But those moments pass and things do get better again.