I'll make a fool of my self in front of my

• Family 
• Friends
• Business Colleagues

Not the case at all, actually the opposite response is much more likely: people will respect you for having the courage to speak in public, remember the survey - more people are afraid of speaking in public than any other fear. By standing up you have earned their respect. 

I will forget what to say.

This is easily dealt with by preparation. We take the text and develop it, prepare it and rehearse till we are competent and comfortable.

We could go on with the excuses, I am sure you could come up with a whole host more, but they are exactly what they say they are excuses not reasons.
What actually causes this nervousness is a sudden rush of the hormone adrenaline into the nervous system, it's the 'fright or flight' syndrome.

When we are confronted by a threatening situation, such as an aggressive dog snarling and barking, the adrenaline stimulates our physiological reactions so we have a better chance of defending ourselves or escaping.

This is nature's ingenious way of helping us to save our skins.
As speakers we learn to use what nature has given us to our advantage. We start by recognising this nervous tension we feel as we are addressing an audience as a form of positive energy. Being nervous is healthy it shows you care about delivering your message. You value looking and sounding good.