Yours is the archetype story of woe I have heard from dozens of athletes who overtrained themselves and ended up wondering what happened. I’m not sure if you’ve read the Overtraining article on the site or the sections in our books on OTS but you might want to start there. You also might want to read our article on hrv and why we do not rely on hrv.
OTS is a complex medical condition that most doctors are not trained for and have never seen. Your docs response was typical. You are healthier and fitter (even in your current overtrained state) that 99% of his patients.
Sadly the only known cure for OTS is complete rest. You must stop all training immediately. The insidious effect of OTS is on the autonomic nervous system. That’s why your resting HR is elevated. Keep monitoring that during this period of total rest until it returns to normal. how long with that take? As extreme as your case sounds I would expect several months will be needed to recover from this.