Advice needed for 26 M

Hello, I need help regarding my new symptoms. I have been on propranolol 40mg long acting tablet for Tachycardia for over 2.5 years and my resting heart rate was always 80-85 and bp around 135/90 always even when i took propranolol 2 times a day in starting and then it became once a night and i was diagnosed with sleep apena too.
Now from last one month i have symptoms like palpitations and burning in chest and went through all the tests ekg(multiple)
And holter also for 48 hours my previous 2d eco done 6 months back was normal
What I have started to notice now from last one month is my resting heart rate is around 60 to 65. When I lay down and sometimes goes to 58 as well, and I have recently noticed that my BP also that always stayed high is around 120/80 and sometimes 109/77 as well, so I have not changed anything my lifestyle, my anxiety levels, I have only risen and also my acidity issues have risen although after the Holter and ECG test, I was diagnosed with POTS but I am frightened that what has caused this change in my body that the propanol has started to affect me more or is something seriously wrong with my heart. I am very frightened. No Dr wants to listen to me now. What should I do? Is it a pots symptom or is it a new disease which the doctor is not able to catch till now? What should I do now?
Please help