Assuming ur middle aged if you r able to do your daily routine without any difficulty (for example palpitations,chest pain
and difficulty in breathing) you don't have to worry.
I presume you would have done Ecg,Echocardiogram
,Blood sugars and
levels.If they are within normal limits you should probably meditate (practise yoga),
do aerobic exercises or workout in a gym,sleep well and plan a healthy diet with lots of green leafy vegetables.
Consult a physician if you are too anxious and get anti anxiety medicines.