I think the caffeine was speeding up your metabolism too much and that was causing the anxiety and weird heart rhythms, I am glad you stopped, it really is not that good for a person anyway.
It took you a long time to figure out you needed to stop drinking coffee. lol
I am only teasing. :)
Don't drink coffee? :-)
It's seems like it's highly variable who responds on coffee with panic attacks, premature beats, etc. I don't notice much of a difference unless I drink lots of coffee. Some people do. In my case, sugar and chocolate is far worse.