Sooner or later, everybody will feel the same way. In my experience, getting over it was on the same order of magnitude as, say, getting over a divorce. Absolutely one of the worse experiences you can have which won't actually kill you. Some pieces of advice I got which really helped:
1. What you need is seeing that small but steady effort yields small but steady successes. Losing weight, or shaving seconds and minutes from a swim or a run, fits the bill nicely.
2. An essential part of healing is to heal your body and health. When your body is strong enough, it will heal your mind.
3. Depression is a lying bastard--don't believe anything it says.
4. IT GETS BETTER!
