Hi I bought the FF for this very same reason I was very healthy 53 year old active every day and received double Pfizer. About 5 weeks after 2nd dose I had first episode of Afib and second about a month after that. I as well have asked doctors about a link to the vaccines and they have all said it is very unlikely but I have been sceptical. I also am not planning on booster until more information about links. I truly think the Afib was caused by the vaccine but do not seem to be able to convince anyone else.
Thanks for sharing your story it has helped me!