YE just posted a quote from Sean Parker where he says "Running a start-up is like eating glass. You just start to like the taste of your own blood."
And that is so true. You can get addicted to your own business. But you can also kill yourself. To be successful, you have to put in a lot of work. But at some point, if it hasn't happened and you're sacrificing your happiness it is time to reevaluate I'd say.
My blog has posts helpful to business owners and freelancers. http://www.pinebeltwebdesign.com/blog