welcome to HCM.
are abnormally high. what were the T3, T4 levels?
was ultrasoundthyroid or a scan done?
was TPO done?
have any other problems?
till then can not comment exactly, as endocrinology is complex. no harm in starting 25 ug eltroxin/ thyronorm
and retest TSH. it is very small dose.
pl. revert with additional info and would be glad to answer.