why is my tachycardia getting worse - truly desperate for an answer

f 23, 140 pounds - i currently take metoprolol 12.5-25 mg a day. a few months ago i had 5 days of an inhaled steroid (trelegy) and i’ve been tachycardic since with absolutely no explanation from primary care, cardiology, electrophysiology, endocrinology or neurology.

i took 37.5mg of my meds today and im still sitting in bed unable to sleep because my heart is over 100. i can’t live like this anymore - i have a deep fear feeling that comes with intense palpitations and flutters. usually when i take my medicine it’s helpful but it just won’t come down from 100+ today.

all of my tests so far (echo, holter, ekg, stress test, cbc, thyroid, ana) have come back normal, except that i failed the tilt table test and had some abnormal lab results (high dhea & aldo/renin ratio) but the endocrinologist told me she can’t make a diagnosis yet.

any advice for further testing or what this could be would be deeply appreciated