Given that you have heart disease in the family you should at least make an appointment to see your physician for an evaluation and risk factor modification. You do not need to go to the ER unless you have acute chest pain or shortness of breath.
Not to the point of going to the hospital, but concerned enough to call your doctor, describe your symptoms, and get an appointment to explain what's going on.
The hospital really is for emergencies. To me, it sounds as though you are not acutely ill now, but have some things that need to be checked out in the near future. Your doc can do a basic EKG, listen to your ticker, look for heart-related (or other ) symptoms, and decide if you need to see a cardiologist or are sick enough to be hospitalized. This can all be done probably in a few days, and during regular working hours, rather than in an after-midnight panic.
Of course, if you suddenly find yourself drenched in a cold sweat, violently nauseated, unable to breathe, with horrible crushing (not minor) pain in the middle of your chest, then by all means call 911.
Anxiety can easily be misinterpreted as a heart problem, they cause similar issues. I think to be on the safe side I would mention these things to your Doctor who may want to organise an EKG. Have you had your cholesterol levels checked? When was your blood pressure last checked?