Ahh I had a similar thing a few months ago.
Felt faint, shaky, hot flushes, etc etc…
I had experimented with porridge which caused a spike, then exercised to bring it down.
@Andrew Colvin says I dropped my BG too fast and too low, went to 3.3 or something silly by the time I tested.
I did the same as you, ate a sweet.
It's not a dangerous hypo like a type 1 gets.
Your liver kicks in and straightens it all out.
But I did feel very ill for the rest of the day.
Your body just isn't used to the lower BG yet is all … I think anyway