I have the same problem, it doesn't matter what I eat..I take Zofran before I eat and sometimes afterwards.. I had a left adrenalectomy 2 yrs ago and have not been well since Ive had to quit my job and cannot drive now because Im never sure if im going to pass out or not, soooo I know how you feel, the doctors are now thinking I have adrenal insuff.
When a person eats, a body normally sends blood to the digestive system. But it sounds like stuff is not normal.
That sounds like something with your gastric system - or your cardiac - hence you are not getting warm. There can by thyroid stuff where you can be cold - but the gastric stuff would lead elsewhere - what tests have you had done and what docs have you seen?