Not sure I agree with this. If you're unsure about what you want to do, I think you should take some time in the 'real world' to figure that out.
But, those are all good questions you raised. I would start by contacting the school and asking them about letting you out of your commitment or deferring - they may be supportive. I'm sure your letter writers will still write good things later on - I wouldn't worry about that. I think the toughest thing will be finding a good job right now. But I still think working awhile is invaluable and will help you later on when you are coming out of the grad program.