How does anxiety cause brain fog, lightheaded feeling/faint feeling? always assumed it was more of heart attack feeling. dont have fast heart/breaths.

Possible & rule out: Anxiety certainly can cause lightheaded/faint feelings, but you also want to make sure there is not a physical explanation that has not been addressed. If you have not discussed your symptoms with your primary care doctor, I recommend you do that to make sure something isn't being ignored. In addition, pay attention to the situations in which these symptoms occur for clues to possible triggers.