Most of our behaviour is based on what others are going to think about us. Being a part of the society a lot of our actions and thoughts are derived from what we see and learn.
Our natural tendency would then be to fit in to what the society or other people would think as 'correct' or 'good'. Does that not stop us from being our authentic self? Yes it does. The less we focus on how others are going to think about us, the more authentic and true we are going to be. It is a blissful state to not think about what others think about us. How do we do it?
The mean things that people say, they are saying it about themselves and not to you.
Be true to yourself. Write down your beliefs, experiences and what you are learning from them. Try to perceive yourself though your own journey.
The worst thing could be said in a beautiful manner. If someone is criticising you to bring you down instead of helping you grow. You do not need that information.
Someone's mean words are in their head and their feelings. It will never affect YOU adversely if you don't let it. Something to think about!
You have one life! Eliminate the toxic sources that bring you down. Trust your intuition. You are growing every second. You are living through your journey and nobody else can feel what it is like to be you.