Hi,i Am 32 Years Female,i Am Suffering From Hypothoyride From

hi,i am 32 years female,i am suffering from hypothoyride from past 10 yrs,i am taking lelthroxine 75 mg.but from 3 days i am having dizzines and and feeling very lowand i am having some pressure in throat in front and as well as in back neck too.yestrday i went to emergency to check whats wrong with my health .all my reports are normal even in my blood work the thyroid levels came out normal.will this be a reson of thyroid.i am sick of this condition please help me out.