Is it worth it to leave me full time job for a part time one if I'm being treated badly

If you are stable enough to do so and you KNOW the other place will be better. Lots of part time jobs are just as bad.

if they treat you badly, leave them. i know, feeling unhappy for a longer time can make you sick. you could keep on looking for a full time job while doing the halftime one, maybe

My sister works at the part time place. So I know it's good. This one. It's gotta bad for me since I had ONE unhappy customer complaint.