Rhi, I am find I need to also eat...not all the time but just about and if I dont, not only does MS comes with a vengeance but I feel like crap. I seem to be needing carbs and protein mostly, so I try to stick to low fat and lower GI carbs if possible
I am a borderline low blood sugar person even when not pregnant and I turn into a nightmare when I dont eat regularly, so you can imagine what I am like when pg.
Dont forget that tiredness is a big part of the first trimester too, so that prob contributes to your general unwellness.

I would go see your Dr and check your blood levels for sure (you can never be too safe) and I am going to look into this Brewer diet myself as I don't want to put on too much.
A dietician doesnt sound like a bad idea either.

Hope you feel better