Welcome to HCM!
After reading your question it looks that you should see a cardiologist / or a doctor atleast once, get your full blood tests done and blood pressure measured. Had I been treating you I would advice an ECG and ECHO to check the status of heart muscles and working.
You have not mentioned if you suffer from hypertension
, or any other illness or if you are on any medicine.
From my clinical experience I can say that the presentation is of short duration but you develop significant distress in a short spam of exercise (even though you are used to it, ), this should not be ignored.
Please see a doctor , preferably aa cardiologist and get yourself evaluated.Till then, it will help you to avoid any kind if strenuous exercise and avoid staying alone/ driving for long time.
Hope you get well soon
Feel free to ask more queries
Dr. Manisha Gopal