It's simply that your story didn't happen to be what she wanted. There are many reasons why an editor might reject a book, including the fact that she just didn't happen to be feeling all that well when your book landed on her desk. Kaye Webb saw its potential. Even Stephen King had to battle against rejection. It doesn't need to take years for rejections not to hurt, as it did with me.
Writing is both the boat and the wind in the sails.
There are many things you can do to help turn rejection into acceptance. First, you should ensure your work is the best you can make it. If you are 'grammatically challenged' or have poor spelling, and don't bother to do anything about it, you will continue to receive rejections. But help is at hand. Read as many books about writing as you can.