Oh man I feel ya, and have experienced this same thing myself. While I know it feels defeating, you should definitely think about how great it was for you to accomplish that period of time and realize that you can beat it. I've stuttered my entire life and I'm 37 now. I've accepted who I am and I tirelessly work at my speech for ME and no one else. Every year I get a little better and every year I feel ALOT better. Take that moment as a win! Think about what you were doing, how you felt, stress, environment, etc in that moment and breathe. I know you can get it and we all got your back