Your self-talk is NB and influences what you think you are (and are not) capable of.
Reframe any negative self-talk with a YET/BUT statement.
Are you a good friend?
Think about how you would speak to your best friend and speak to yourself in the same way.
Actions over Feelings.
Try answer "what can I do about this?" to shift your focus from how you feel to an action that you can control.
If all else fails, use this phrase to stop a negative spiral:
"Telling myself these things is not going to help me or change my situation."