"I now beleive I tried to come out of the fasting state way too quickly!!!
It sounds like you were very sensible about the way you broke your fast, but yes it seems that however gently you were breaking the fast, it wasn't quite as gentle as your body wanted.
"I was miffed that I'd broke my fast and thought all the work I had put in had went to waste."
No way, far far from it :). Wait a few days and i bet you will feel sensational.
"Going to take it really easy and listen to my stomach."