Hi, and thank you for coming to JustAnswer.com with your question.
This IS something concerning. You should make an appointment with your doctor right away so that you can make a plan as to how to manage this - if it is hypoglycemia (low sugar), or figure out what it is.
Do you have any medical problems?
(whoops -- are you taking any medications?)
Here is a link that discusses hypoglycemia that might give you a bit more information about it.
What medications are they?
(One thing I should add is that you did the right thing by taking something to eat. If someone is conscious, one of the best ways to very quickly increase the blood sugar level is by drinking some juice).
Were you just off looking at the link