I as working at as an outside sales rep in a failing company. I had just had my daughter and grabbed the job as a quick (no other option) solution after the previous start-up I worked for went belly up. The manager called a meeting at the end of the month and said he couldn't make payroll. A guy behind me literally started sobbing. I had no money and wasn't getting paid.
So I started a business.
Speak Social, my new company, had three things going for it. I knew social media and marketing very well, it was the perfect time to do it, and it had to work. In less than a year we were very much in the black and we had 10 employees. I've always made payroll.
You hear these rags to riches type stories all the time. Hard work and determination pay off and all that... I'll tell you from experience that hard work and determination is nothing. Anyone can work hard and be dedicated. That's not being entrepreneurial, that's just being a hard worker.
The bottom line is if you are building a business from scratch and boot strapping it hard work and determination is a given. What you need is timing, exceptionally good people around you, and a total disregard for your own security.
My advice is to go all in. Put in ridiculous numbers of hours, make tons of mistakes early and then don't repeat them, and don't think about plan B. There is no plan B.
You don't dip your toe in this, you dive without checking how deep it is. I remember seeing a picture of this child starving in the street in India. I have kept that image in my head. No matter how hard it gets, it isn't that hard. At least you get a shot, some don't.
You are not secure, you will never totally be secure. So don't worry about security, worry about success. My favorite quote is by Goeth "Be bold and mighty forces will come to your aid." I have found that to be absolutely true.