Pregnant and tachycardia

I’m 7 weeks and take propranolol 20 mg twice a day. I won’t see my doctor until next week and they called and said I need to stop taking it and can’t take anything in first trimester... well I have POTS disease and have to take something for my heart I cannot deal with my tachycardia without meds. Just curious to see what any of you ladies took for tachycardia while pregnant