Sally,

The key is to keep on saying them, even if you don't believe them, there will be a magic day where it will click and all of a sudden it will become like second nature. I remember the day it clicked for me. I've been doing well ever since. I promise that day will come, Just keep on counteracting every single negative statement you catch yourself making with positive more self-affirming ones.

Love and Hugs,
Tara