Maybe you need a vacation if you haven't taken one. Guilt vacations where you don't get anything done for a while aren't as good as deliberate ones where you post up 'no support for two weeks, snoozing on beach/gone fishing/Vegas Baby.'

But if you're still into the niche, then maybe the answer is to stop writing code and and focus on business development & QA. You don't need to be always working at the coal face yourself. Perhaps get the freelancers to start maintianing your code base and switch your attentions to product and busines development, plucking the most promising contracters to become employees?

Whichever, don't beat yourself up. It's Thursday now, so I suggest clearing your urgent emails and then taking the rest of today, tomorrow, and the weekend off (ie away from the computer and preferably from your home) to think about what you'd like to be doing each day of the week. Lots of luck!