Since you are committed and don't feel you can back out of the project perhaps there is a way to help you feel less trapped in this project of doom. What if you completed the project as soon as you have the time but delay sending it back to her until spring. By doing to sooner you remove that feeling of I don't want to do this project I hate. You could turn it into a major learning experience on several levels. Do what feels right to you and the doom will disappear.
Good Luck!
Andie :)