So i had lightheadedness started last month and then heart palpitations, i did ecg there was sinus tachycardia with extras systole and i did cbc,tsh,electrolytes check, hb-12.0, iron and electrolytes norma, tsh-9.74 and t3 and t4 normal consulted an endocrinologist and started levothyroxine 50 mcg - its been 7 days i am taking it and the lightheadedness and skipped heart beat is still there. I was told to take propranolol 10mg but while i take it the palpitations are better but the lightheadedness is still there and again the next day i feel palpitations. While i stand i have high heart rate, while sitting heart rate is 80-85 and while i stand it is 110-115. While i walk it goes upto 140