I just want to reiterate what was said above: "Depression can be serious business, do not neglect it, it's not worth it."
Some people simply cannot work/live alone for long periods. I tried it for years myself, but was completely miserable and have since changed my life.
Having said that, little things that may (or may not) help you are: having a workspace with tons of natural light, morning exercise and having a strict and balanced schedule of work/play/sleep. Good luck.
As other people have suggested, try going to a place where you can still work. Maybe ask people at your office to set up a webcam/mic for you(maybe a netbook in the office kitchen?, might get interesting for both them and you!), or during meetings.
If not then think about getting a job where you can go work in an office. Depression can be serious business, do not neglect it, it's not worth it.