Have you vomited? And what did you eat, could it be food poisoning?
I don't think high sugar caused it, high sugar wouldn't cause heartburn.
How far along are you? This happened to me once early in my pregnancy but that is the only time it happened. Freaked me out when it happened though. I would ask your Dr if it continues to happen
Gestational diabetes??? But im not an expert so not sure. Look it up x