Thanks for writing your query.
After reading your post, it seems that your symptoms might have occurred due to an episode of increase in blood pressure while working in your garden.
You should consult your doctor and get yourself clinically examined and investigated.
Following investigations will be helpful :-
1. Blood pressure and heart rate
4. Fasting Blood sugar levels.
5. Lipid profile
6. Cardiac enzymes.
I hope this is helpful to you.