After going through your history I am of the opinion that you do not seem to have any abnormality. Feeling weak and some times some amount of numbness
after the kind of physical activity to which you are adapted is not abnormal and the feeling of weakness can remain for few days following the physical activity, and you need not stop your workout because of it as it will settle down after few days.
During any physical activity heart rate
will increase and heart will start pumping more strongly to meet the demand as the working muscles need more energy so more blood supply and it is normal if your heart rate increases during workout and you start feeling that your heart is pumping.
But, If you still feel there is some problem with your heart then you can consult a doctor and let him examine you and then proceed according to his advice.
Wish you good health.