> "you really need to get your fast heartrate down, if it's not a medical issue then you need serious psychological help",

... then ...

> 1. I went on antidepressants (lexapro), this is not the first time I've been on them and despite HNsers who think they're bunk, it's pretty obvious they have a positive effect

Unwarranted anxiety is a common symptom of depression. The doctor was right, you needed psych treatment.