I went through something similar a few weeks ago. I would suggest that when you decide you need to eat, to first take all possible steps to be calm. If you have a hard time even fixing anything start out with juices and fruit, these are very easy on the stomach. If you can't manage fruit then have smoothies. Rice, bread, pasta are all good to settle your stomach and alll will help you sleep better as well. You need to take care of yourself and realise that this is part of the mourning period. Try your hardest to eat, but remember you are the only person who can help yourself.
Try anything you can to destress, take a bath, workout, yoga....you name it whatever helps you relax do it and you'll feel better. The pain will lessen over time, just be patient with yourself.
We are what we think. All that we are arises with our thoughts. With our thoughts, we make our world.
“When I let go of what I am, I become what I might be.” – Lao Tzu