Nothing is "secure" in this world. Your regular paycheck can be gone tomorrow for a wide-array of reasons. People saved money via investments thinking it was "secure" when in walked Bernard Lawrence "Bernie" Madoff. While he was sentenced, the money wasn't returned.
You are not secure. So, why not be happy? If you have a great idea- have confidence in it. Say yes to it and yourself. There is nothing more rewarding then earning your own money and keeping it! Sure, there will always be Bernie Madoffs in this world. You will always have fear when walking away from a steady paycheck. But if you believe in yourself, and you should, the fear will quickly turn into profit. The hours of working for yourself are going to be longer. You may not make a dime the first one to three years. Your family will barely see you.... but in the end, you are in charge of your destiny and the reward will be great.
If your having fear today to explore your business idea- don't. The worst that can happen is you fail. I've failed. You always gain knowledge from failure and then you can pick yourself back up, dust yourself off and move on to the next idea!
Ask yourself where you are at today. Are you a yes person or a no person?