Hi this is Kitt and welcome. If you have been to the ER and 4 different Doctors have told you your ok but have dx you with anxiety then I would think they may be right.
It feels to me like you most likely have Health Anxiety.
Health anxiety/health phobia refers to an excessive preoccupation or worry about having a serious illness. Often, health anxiety persists even after a physician has evaluated a person and reassured him/her that his/her concerns about symptoms do not have an underlying medical basis or, if there is a medical illness, the concerns are far in excess of what is appropriate for the level of disease. Many people suffering from this disorder focus on a particular symptom as the catalyst of their worrying, such as gastro-intestinal problems, palpitations, or muscle fatigue.
I would like to suggest that you consider seeing a therapist, someone that could help you deal with anxiety.
Take care and know that you can beat the anxiety with help.
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"When you find peace within yourself, you become the kind of person who can live at peace with others."
Not a mental health professional of any kind
Clickable Link: Anxiety-Panic Resources