I think I would be refuting the statement: "I don't know if I want to let that go and get 'better' and not be allowed to be angry anymore." Maybe you can get some leeway breaking it down and writing out the thoughts that come up.
"I don't know if I want to let go because __________."
"I don't know if I want to get better because ________."
"I feel if I get better I won't allowed to be angry anymore because _________."
Sometimes I find some irrational thinking or I can track down the source of what I'm feeling. Most often it was child or teen perceptions that I didn't re-examine.
And example of this is for me might go: "I feel if I get better I won't be allowed to be angry anymore because people might expect more from me or might try to air grievances with me when I am not wanting to because I am still angry at them."
Refutation: That's ridiculous. if I'm better I still might get angry from time to time. I'm an adult and I can be angry if I want to and am prepared to accept the consequences that come along with it. No one can tell me what I'm allowed to do or not to do anymore, it's up to me, my decision. What's wrong with people wanting to expect more from me if I get better? Nothing. I can deal with people's expectations if or when the time comes. What if people want to air grievances? Don't I want to air grievances at times too? The world isn't going to explode or end if that happens, as I get better, I can find new tools to learn how to handle these situations."
It's sort of a personal dialogue for me... just an example of what might go on in my head. Picking apart the thoughts sometimes really can be helpful