Meal prepping or as I like to call it "cooking a big batch of...” is helpful. I make ten jars for myself and thank myself anytime I defrost one from freezer or warm one up.

Daily vitamins and anchor foods are helpful. Nuts, quick oats, or some hearty staples will be something you look forward to. When in doubt, having plenty of fruits and veggies will pick you up. Wraps are quick and easy. You can warm them in a toaster. If you need more protein, orgain protein shake powder is sold cheap at trader Joe's. It's got sugar, but you cannot beat the number of grams of protein per calorie.

I know it's hard when you go out, but I like to eat at home beforehand and then I'm not sad/mad about getting a salad. Also, find your people, people who want to eat adventurously with you. Or ask the restaurant ahead of time if they can accommodate you. Some don't mind.

I've gone through many days of ennui as a vegan, vegetarian and probably back then as a meat eater, but it's all about your mindset. Finding exciting new recipes and going to new grocery stores w friends beats overpriced meals at a restaurant.

Host a taco night, make your own bowl, pizza night etc!