I Have Been Diagnosed With Atrial Fibrillation A Couple Years

I have been diagnosed with atrial fibrillation a couple years ago first off. Just a couple weeks ago I started to feel a weird sensation in my chest. When it happens it feels like my heart stops and I get the worst feeling of doom. Then 1 or 2 seconds later it feels like a thump in my chest and it starts pumping again. My resting heart rate is anywhere from 90-100 it has been that rate for a few years. Also I just started noticing a strange taste in my mouth and its kinda like the roof of my mouth may be numb. Just a strange sensation and taste in my mouth.