First, I let myself feel it. I don't judge myself for feeling it, I remind myself that it's ok to feel this way, and I remain aware that it will pass. Knowing that it's ok and it will pass keeps me from getting much worse. Not pushing it away allows me to take the time to validate how I feel to myself and get those feelings out in a cathartic way.
Then I remind myself of who I am and who I want to be.