My therapist taught me a question to use when someone, anyone, says something hurtful or I perceive the comments as snide -
Just calmly say, "What do you mean by that?" It throws the whole issue back in the face of the person making the remark - or just walk away. Do not let someone else take you down when you know you are fine.
You can also choose to eliminate negative people from your life, yes even family members...............or at least distance yourself from these negative people. Negative people can be a source of energy drain. And deeply unhappy people will want to bring you down emotionally, so that they are not down there alone.
Take care and remember you must love yourself first !