Most people don´t make it. Sorry to be so direct, but it´s quite true. Entrepreneurs are well known to be very ambitious and optimistic about business which is a good thing, but this also has serious consequences. Over promising and underdelivering is quite a common way to fail with your startup and is a common fault among first time entrepreneurs. Long story short, starting a business is very stressfull and can be deadly! 
About 2 years ago at a periodic checkup the doctor asked me how I was feeling. My answer was that I had trouble sleeping, found it difficult to relax, never felt 100% rested and in general was quite stressed. After some blood-tests we found out that the brain was producing the wrong amounts of T4 and T3 and that I had developed hyperthyriodism which made my heart beat very fast and irregular at times. WOW! I had no idea!

Time to change things!

One of the biggest challenges for me in the upstart was to figure out how to have a work-life balance. Even though you want to work all the time it´s actually ineffective to work all the time and it´t not good for you! I strongly believe that if you do the 90+ hour workweek for to long you will achieve less. As posted in The-Upstart´s twitter feed I have recently finished reading “The 7 Habits of Highly Effective People” by Stephen R. Covey and I strongly recommend this book to all entrepreneurs. The best ideas, solutions, innovations etc. I have come up with have popped into my head when I´m not in the office. It´s very important to spend time learning how to work smart or as Stephen Covey calls it “sharpen the saw” as seen bellow. As Jim Rohn recommends and many others; spend more time developing yourself and your skills than on your business. If you have the “get rich quick” mentality you will think this is bullshit, but for me its a marathon, not a sprint. 
In short the elements that you need in your life are seen bellow. If you are passionate about what you are building its unlikely you will be able to 100% switch off your thoughts and healthy distractions can be the best thing for you in developing your company. There is a lot of great material on how to get better at this aspect of entrepreneurship and I strongly suggest checking some of it out for yourself.
“Nature does not hurry, yet everything is completed.”

Here is some necessary info on mastering the ups and downs of running a business. Click Here