If a toxic person is making your life miserable, one way to soften the blow is to stop taking them so seriously. If you really view them as toxic, why would their opinion mean anything to you? You should never let your opinion of yourself change based on the words of toxic individuals.
Instead, take everything they say with a grain of salt. Ignore them entirely if you can, and focus on the positive people in your life. They are the ones whose opinion really matters!