Should I resign from the PTO?

I ran for the office of PTO secretary last May, and bumped up to VP before the end of the election because no one else would run a higher office. The previous year's president further bumped me up to president, and then later demoted me back to VP after she personally requested another woman take the office without this other woman even wanting to run for an office. So now they have a large festival planned for Saturday, which I have no desire to participate in, and furthermore the president has handed in her resignation. I want out of this badly organized organization; it's become a very negative experience for me.

What would you do? My eldest is in 1st grade, so this is my first PTO experience.