How to get over your fears and just do it

Isn't it obvious?? We're all running around, oblivious to the fact that any moment it might all be over. ANY MOMENT!!! We all understand and know this, and still, we pretend like it's not a reality. We think it's not gonna happen to us. There's a quote which presumably is from the Buddha - although I think it seems that way too many quotes floating around Facebook these days are said to be by the Buddha just to give them some sort of validity- anyway, the words are so true:
 -"the problem is, you think you have time"
So true. We think we have time. But we don't! In a blink, it's all gonna be over. 
Sometimes, if I'm facing a situation that I find difficult, I remind myself. "Before you know it, it'll all be over, and you'll be regretting not living fully, not being brave, not doing this thing that is in front of you. It's uncomfortable and it's scary. But what's the other option? Coming to the end of your blink of a second called life, and not having done it? Don't be scared. Go for it. Your life is happening NOW." 
It always helps me.