That certainly is challenging. I cannot eat onions, so i know from experience they tend to be in everything! I am also a vegetarian, and highly lactose intollerant. You might want to start by searching for vegan gluten free recipes, then eliminating those that contain other ingredients you cannot eat. Also, try thinking of substitutions. For instance, if you can tolerate garlic, a little of that can fill in for onions, and kale or cabbage might sub in for spinach or lettuce, etc. Since you have to home cook a lot on a limited schedule, once you find some more things you like, I would cook them in large batches whenever you have an afternoon off, and then you know you have several things ready to go that you know are safe foe you to eat. It's definitely difficult, bit its worth it to be healthier and in less pain.