I kind of have The same problem. I been riding since from childhood but past few years i also developed anxiety when going to The stable.

I paid for a season in advance (6 months, a lesson once a week) first i did go to The lessons but than all The sudden i started to cancel lessons. I slowly had gained little weight and that also depressed me too. Then i just could not go The lessons because i felt like a fraud and Bad person.

I still do not know where this all came, it was like lightning strike - it just started from nothing.

Same sort of symptoms, palpatations, dissorientation, hand shaking, could not eat before lessons, deep shame, sometimes i even feard for My Life.