See those people who are telling you that you are not good enough as your greatest teachers. When you can do that, you conclude that part of your contract with them.
People tell us these things because they help us to learn about ourselves. Ask yourself how each one of these negative people has already helped you to change, grow and gain wisdom. If you can answer the question and feel gratitude for the change in you, then you will also feel true universal Love, not only for this person, but also for yourself.
The main thing is being aware of your self (and I deliberately use two words), and be aware of others. That awareness will help you find more answers in yourself, and that is what also helps grow your psychic ability.