Self-talk is very important in the pursuit of positiveness. You just shouldn't listen to your self-talk in your head, sometimes you need to communicate back clarifying how you feel.
Here is a note I wrote to my core self.
"Today, I will no longer allow others to define who I am. I will become mindful of the difference between me in the moment and me of the past who only resides in my memories. I will know that my past thoughts, actions, and feelings were a result of hurt done to me, and definitely were not my fault. Therefore I am no longer going to own them. I will believe strongly me and my positiveness. I will accept all that I am now. I will remember that my experiences flow like a river and in a moment all my experience will turn into history. My goal is to recognize and accept my core self totally, my authority and appreciate me daily."