...isn't the feeling of helplessness, isn't the loss of will, isn't the inability to find joy. It's the way that it pervades the rest of your life forever. It's the paranoia that you develop, even when you're not depressed. You have a bad week and don't feel like going to work? You might be having a relapse. Is an important decision looming? You honestly can't say what you'll do if it doesn't go your way. Other people have major problems and come to you for help? You worry that you won't be able to take it all in healthily. Want a drink after a tough day at the office? You keep record of every sip and every desire of that sip, just in case it's a sign of something more dangerous. Need a good long cry? You are afraid that you won't stop.
It's the paranoia that sucks most of all. It's like you are depressed, even when you're not.