You're running a marathon
I'll be the first to admit it: I can work myself to death. Paul Boag recently wrote a great article about the false "badge of honor" regarding long hours in the tech field. I love what I do, and I am continuously grateful that I am able to make a decent living in software. But I'm also prone to burnout.
His article really hits home for me because I've been burnt out a couple times in the past. I'm still trying to improve my self-awareness, but unfortunately burnout is like bad breath: generally the people around you notice first. So far my main red flag has been "Do I feel like I'm sprinting from task to task?" Despite what some startups believe, running a company is a marathon.
Over the years, I've been approached by numerous people asking how they can break into software. How hard is it? How smart do you have to be? Which language is best? My main answer is always: to succeed in software you have to enjoy what you do and you have to be persistent. Software changes monthly, and sometimes it feels daily. At first enthusiasm will carry you through long hours reading and playing with new libraries and frameworks. But when you start picking up your 5th language and your 15th web framework, your motivation is primarily going to come from enjoyment. The key is realize you're not sprinting to an finish line. You're running a life-long marathon. I think the same philosophy applies to succeeding in business.
I almost edited the previous paragraph to say "career-long", yet when I quantify how many hours of my life will be spent earning a living, labeling it "career-" just doesn't seem appropriate.
There is nothing wrong with hard work and I am certainly not promoting laziness. However over-committing yourself or coming home unhappy is a recipe for disaster. Make yourself take enjoyment from your work and from outside of work. And if you can't, I wish for you the courage to make the necessary changes.