Subacute Thyroiditis

I’ve been researching for weeks and trying to not psyche myself out about my health issues but there’s barely anything out there about subacute thyroiditis. I was diagnosed on January 28th of this year. Went into the ER with a 186 bpm and found that my levels were high. I already had hyperthyroidism before this situation. I caught the flu and two days after I got over it, I felt extreme anxiety, racing heart, and just an overall out of it/inebriated type of feeling. Got my diagnosis and I’ve been on 10mg of Propranolol ever since. But it’s been about two and a half months and the Propranolol seems to be doing nothing for me anymore. Either that or my symptoms are getting worse. I still have a heart rate of 140 most of the time until I’m sleeping then it goes down to 49bpm. I also feel like I can’t catch my breath sometimes with occasional slight chest pain. I’m just curious if anyone else has experienced these same symptoms. I’m feeling hopeless and scared.