I honestly don’t know if this will help, but I started investigating mindfulness meditation. One of the things I learned, and this is my interpretation only, is that our mind is like a random thought generator. Try to sit quietly for 5 minutes and think of nothing. Within 20 seconds you’ll probably have some thought. Keep trying to clear your mind each time that happens for that full five minutes. The point of this exercise is to notice that our internal environment changes constantly. Our thoughts and emotions are like the weather. The weather of our planet is somewhat predictable, but not 100 percent. Our internal “weather” is also only partly predictable. My suggestion is that maybe you expect more predictive power over your thoughts, emotions and behavior, but that perhaps understanding how your system changes and reacts on the micro level (e.g. through something like mindfulness meditation) might help. We humans have a natural tendency to expect things to be solid and unchanging. But change is constant and it can help to see change in all things big and small. Exploring this might provide acceptance of your changing nature. Perhaps. I can only say that it helps me. There have been some interesting scientific studies of how we behave and then unconsciously produce an explanation of the behavior after the fact. It points to the fact that we have sort of an “illusion” about our mental/behavioral consistency. Some folks even posit that we have no free will at all, but I think that is a little too extreme. My take is that we do have free will, and we can manifest feelings and behavior that is more “congruent” with who we wish to be. Exploring some ideas and practices from mindfulness meditation might help you understand yourself a bit better.
All the best