I also feel like I’m highly empathic and can relate to your experience. I’ve just been diagnosed with ADHD and I get some RSD type emotions too. I really don’t think everyone who has ADHD is like this, because I’ve met quite a few but I’m guessing there are a few of us empaths that also have ADHD.
I’d suggest that the intensity linked to ADHD emotions play a part in this phenomenon but that ADHD it’s self is separate from the basic amount of empathy people have. So, if one is already highly emphathic – then ADHD might magnify it. If you’re not overly emphathic (and/or there is a lack of interest in other people’s feelings) then it’s at a normal or below normal level.
Hope this makes some sense courtesy of my weird & wonderful brain.
Surround yourself with good people and live a wonderful life.