i would ask your doctor if it's possible that you have panic disorder. to me it sounds like you're having "baby" panic attacks but i'm not an expert. i've had panic disorder for about five years and that is how mine started.
it feels like my heart is racing but my pulse rate is normal and i feel out of breath. what could this be? . i do suffer from anxiety. i have taken natural supplements that promote relaxation and that usually helps with my anxiety. recently my heart has been acting this way and i've tried taking the supplements thinking its part of my anxiety but nothing changes.