Reaction to Stess is Different!

Has anyone else had this experience? I'm working on a big stressful project at work with lots of deadlines that I'm extremely unhappy about and in the past I would've made frequent trips to the snack bar and/or vending machine for chips/M&M's to munch while I worked. And I would've totally rationalized it too! Now when I get stressed like this I totally lose any appetite and even have a little nausea and need to force down protein drinks, can't even think about eating any food, just the thought makes me sick. How weird is this? It's like my brain has been re-wired.