I suffer from terrible nerves!?!

I suffer from terrible nerves!?

i love to sing, i write songs, and practise singing at home all the time.
but when i come to perform i get soo ridiculously nervous! i actually dread performing, which i shouldn't because i know deep down how much i love to sing!
my family and friends are so supportive but nothing seems to help!
my grandmother wants me to sing at a concert she's organising in about 3 weeks time, which i'd really like to do for her. but i'm ALREADY starting to feel sick at the thought of it!
what shall i do?
please, does anyone have any advice?
thank you:)

I have found the only way to get over stage fright (besides for preparation) is simply to do it. You will be nervious at first, but the more gigs you play.. you will slowely start to get better and better

No worries.. think whats the worst that can happen? People wont like yah.... soooo what.

you have nothign to loose so go for it!