I'm kind of in the middle on this one...from the outside, I agree that it seems there is a PTSD-ish reaction here that may have been exacerbated by the interaction with your ex earlier. But I also take GREAT umbrage when people tell me something like "I'm sorry that you misinterpreted that," or "I'm sorry that you reacted that way." That is SUCH a non-apology. Then again, it is so common in our society that I think a lot of people say those things without realizing how ridiculous they are.
I agree that some time and distance, and maybe a good talk with a therapist, will help you sort through this.