Why Is My Brain Tormenting Me?

I have been working on an online course that I created and I have been tortured by my own brain every step of the way. “You’re not good enough,” “it all sucks”, “this is worthless” are thoughts that I’ve had to overcome and deal with. Now I am almost done with my course and getting ready to launch and my brain is saying “start over and redo all the videos.” In watching my videos back and I see how I could make them even better. Is this something I need to listen to? Or is it just my brain sabotaging? I think I know the answer…. the brain is never going to shut up, is it? I find myself getting quite frustrated with these thoughts. Why is the brain so mean???