Keep pushing forward. Don’t give up as long as you still have something to give. Nothing is really over until you stop trying.
Don’t be afraid to admit a mistake. Being less then perfect is the common thread of humanity. When you realize that you’ve made a mistake, apologize and then take immediate steps to correct it.
Accept your emotions. It’s okay to feel sad or angry. Part of believing in yourself is accepting your feelings. To deny your feelings is to deny yourself.