First of all, you're going to have to have a willingness to get out of your funk. Without that, there won't be a chance for change. As depressing as your routine is to you, there's familiarity in it, which provides a sense of security, even though it doesn't feel good. So, you're going to have to be willing to break out of your comfort zone. Do anything other than what you've been doing. (Nothing harmful to yourself or others, and nothing destructive.) Look for things to enjoy. Just little things, no matter how insignificant they may seem. When you find pleasure in something, no matter how much or how little, milk it as long as you can, and remember that feeling. You will have greater resolve in finding that feeling again. Gradually replace your old habits with new ones. When the new habits take on a momentum of their own, you'll notice the momentum of the old habits start to fade away.
Find anything that's fun. Find a sense of love in everything you do. Find ways of serving your fellow man. Provide service to people and the community, even in the smallest of ways. Just a warm, sincere smile can change someone's life.
And, don't be so hard on yourself. Give yourself a break. Know you are worthy and deserving of a happy life just because you exist.
Good Luck.