I'm going through a whole pile of stress myself at the moment and I've gone the opposite way, I just don't feel like eating. When I do eat, as people keep telling me that I HAVE to eat, then it's not long before it makes a reappearance.
I'm also not able to sleep at the moment, I've tried herbal remedies, sleeping tablets from the doctor, alcohol, and nothing seems to work. To say that I'm on my knees at the moment is an understatement.
So this is the big difference between feeling under pressure, and actually suffering from clinical stress. When people have clinical stressed they tend to not eat, not sleep, turn to alcohol etc. When they are feeling under pressure, they tend to eat more as a diversionary tactic (if I eat I can avoid thinking about the thing thats putting me under pressure), hide away etc. These symptoms are actually more similar to those of depression rather than clinical stress.
This is not to underestimate the impact that feeling under pressure can cause to your life, but as a society we tend to use stress to describe a whole bunch of things which aren't stress In fact, a very small minority of people have ever suffered with clinical stress, but the vast majority of us have at some time been under considerable pressure.
So

back the OP's original question - via a rather convulted route admittedly
If I find myself reaching for food it usually means one of 3 things. 1) I'm hungry. 2) I'm under pressure and trying to divert myself. 3) I am depressed.
If I'm hungry, a carrot will do the trick. So thats what I start with. If I'm under pressure, I try to determine what situation I am trying to avoid and why. If its 3, I get myself quick smart to the doctors.
Kittenkat. if you haven't already, get yourself to the doctors, get signed off work if you can afford it, get referred to a counsellor, and don't drink to try and sleep - It doesn't work.