I have gestational diabetes and when my sugar is high, my chest hurts, I get shaky a little, and see dark spots so it's possibly your sugar and that could be why eating makes it worse.
It sounds like it could possibly be blood sugar, but i would have thought eating would help, not hurt. I sometimes have low blood pressure and it doesn't make me shake. It does cause the other stuff though. But a few times my sugar has been super low and that DID make me shake. Also causes the other stuff. Food helped after a few minutes. I dont remember eating ever making my bp worse. All bodies are different though. Might be a sickness. Really hard to say from a distance. Would definitely ask midwife.
How many weeks are you? Could just be a stomach bug or morning sickness. I would treat it like a bug, broth,crackers 7up and for sure electrolytes and water. It never hurts to call your mid wife even if you have an appt tomorrow.