No, you don't have to start again. Finish the game you are playing now and you will be given the option to start a New Game+. This allows you to carry over dresspheres, garment grids, percentage, items, etc so you don't have to start from scratch. On your second playthrough you should give the Awesome Sphere to the other side, eg, if you gave it to New Yevon in the first game you should give it to the Yout League, and vice versa. I'm currently on my second playthrough. I got 86% at the end of my first game, and I reached 100% in the middle of chapter 3 of my second game. Don't despair, all is not lost.