I am recently being treated for low iron and vit d levels.
Every day I will have a period of time when I feel very tired, my breathing goes weird (which can be managed with breathing exercises) and my chest feels weird, slightly achy. I can't describe it as fluttery, and if I feel my pulse it feels regular, but I just feel weird.
This does happen more when I'm stressed about something, and if I have a good day, clear of this, the next day it will usually happen more. It can also happen when I do too much, or walk up a hill too quickly, but then I usually immediately start feeling anxious, so I have no idea which came first.
If I'm feeling like this, sitting down quietly and completely distracting myself makes it go away, as does having a long soak in the bath.
So this probably sounds like I'm typically anxious, but I am worried that there is something wrong, but it's being missed as anxiety. (Which probably sounds like anxiety talking!)
I do have propranolol to take when things feel very bad, and it does seem to help me feel less anxious, but I still get these episodes of feeling weird.