I have kids with ADHD who all think I am, what I tell them to do when they get too skinny (maybe it is racoon food, but)
Buy Triscuit crackers and hummus and olives and nuts. High calorie in a small package but not unhealthy, some good fats are calming.
Take a banana with you, and a water bottle. Sandwiches are also such good travel food.
In a pinch, a spoonful of peanut butter. But the one that doesn't have high fructose corn syrup.
Try to stay away from refined sugar until you are eating better and more regularly. Don't be afraid of caffeine though.
It is hard. I have done full time work and school, it's hard for anyone. It's not you. Can't say life ever slowed down but school was the worst for me.
Sorry, just read down and saw you need to cook for someone else too.
Chili in the crockpot.
Canned beans on rice.
Those cooked chickens from the grocery make good quesadillas.
Ramen, you can throw shrimp in there while it's cooking, or some of that leftover chicken.