You’ve got to love yourself.
If you love, respect, trust yourself enough, you will know your own value. It won’t be decreased or increased be how people think and talk about you. You won’t feel everybody’s picking on you and get offended. You won’t need to seek praise either.
You don’t need to ask for a reward when you help others. You do it because it’s the right thing to do, not to be a hero. You know whether you are a good person ever nobody sees it.
It sounds like not caring about others’ feelings and doing whatever you want. It seems self-centered. But first, you can’t satisfy everybody. If you try to make everybody happy, you’ll disappoint everyone including yourself. Do what is right. Second, when your feelings won’t be affected anymore, you won’t care about them. You don’t care about yourself that much. It isn’t self-centered. It’s selfless.
Love yourself, so that you can love others.