I have found that the fight/flight reaction our body has is A NORMAL RESPONSE to things like this. It is important TO ACKNOWLEDGE THAT.....but then as my psychologist says, have a "teflon mind" that let's it go instead of holding on to it.
You said you are getting better at this & THIS IS IMPORTANT. Changes in how we react aren't magically gone immediately. It takes time & practice.
Lol....when crap like that happens to me, internally in my mind, I thank them for the opportunity to practice so I can get better at letting it go. I have found if I put a positive thought ( like giving me a chance to practice new skills) to negative things that happen it also helps me get past them quicker & practice that "teflon mind" skill.
I have had a whole hornet's nest full of stuff like this lately but for me, I have found that my peaceful daily life is what grounds me & definitely keeps me distracted from focusing on the negative