Thanks for using Healthcaremagic,
After going through you available details it is clear that you suffered low blood sugar level (Hypoglycemia).
There are many causes for low blood sugar level hence it must be investigated properly.
You should visit an Endocrinologist
and appropriate tests including oral glucose tolerance test
. with ultrasonography
or MRI of abdomen to find any tumor secreting insulin.
There are reactive hypoglycemia
cause is to be searched and treatment depends on cause.
In the mean time avoid exercise and take frequent starch meal to maintain blood sugar levels.
Hope this information is useful to You.
Wish You good health.
Dr.Akhilesh Dubey M.D.