I am 24 years old female. weight : 57 kg , height : 5.3'. I recently got diagnosed with Hypothyroidism. My blood test results are as follows:

T3: 90.41
T4: 6.90
TSH: 9.04

My doctor has prescribed me : Thyroxine sodium IP 50 mcg Eltroxin

Does this prescription looks legit? ; I started with the tablets 2 days ago and have some problems of uneven heartbeats ( mostly fast), difficulty in breathing, mild headaches.Please suggest should I consult my doc for change in my dosage or is this just my body.. getting used to Eltroxin as I have just started with the meds...