Good fats and fatty-acids, also.Do you seriously want a nutrition lesson?
The title is funny, but your post is somewhat troubling. Neither cats nor dogs would do well on such a diet as you describe (although peanut butter is good). In WW2 many prisoners of war were given a diet of only rice and eggs, and some of those were denied the eggs as punishment. When deprived of the eggs for long enough they would go blind before dying.
When things are rough it can be difficult to keep motivated, it's too bad that decent nutrition is necessary to feel good physically and that the two are so closely tied in other ways. I'm sure you realize that you need protein. I hope the sandwiches aren't on wonder bread. Not sure what else to say, but please look after yourself better.
Our brains/nervous systems are basically made of them.
The most important nutrient for a child under 7yrs old?
Cholesterol. Brain development DEPENDS on it's abundance and availability.