I'm pretty easily overwhelmed and pretty tough as well. I think I'm tougher than I used to be. There's been a lot of hardship along the way. But that's what life is. And it's how you deal with those things, and how you let them shape you that makes you a better person and defines what sort of person you're going to be.
If you want to be an entrepreneur, it's not a job, it's a lifestyle. It defines you. Forget about vacations, about going home at 6 pm - last thing at night you'll send emails, first thing in the morning you'll read emails, and you'll wake up in the middle of the night. But it's hugely rewarding as you're fulfilling something for yourself.