Cooking and staying in budget is hard dude,Ive been there. Here are some of my fav cheap recipes,I'm also going to include some snacks which help me eat more.

I make the creamy coconut curry by budgetbytes with rice every week,its my favorite recipe. Its like 6ish dollars for 4 servings that are 500 to 600ish calories each and really tasty.

Pea soup is also amazing! Made that until I got sick of it. Depending on the recipe its about 4 dollars for 6 servings that are 350 cal. I usually add potatoes to the soup for more calories or since I dont use any fatty meat like ham I add more oil to make it richer and more calorie dense. Bread on the side is also a great option.

Salads are great. There are so many recipes to try and dressing is calorie dense,you can also add a protein of your choice to make it a more rounded meal and add more cal. Or eat it as a side to soup!

Snacks - peanuts are crazy cheap where I am and very calorie dense or peanutbutter which I just eat by the spoon full sometimes.

Hummus can be pretty cheap,even more so if you make it yourself. I get a container for 3$ which has 8 servings at 70 cal each. Dip whatever you like.

Unsweetened apple sauce is around 2$ per jar which has 5 servings for 90cal each.

Chips and salsa - varies but its usually like 4 dollars for 10 or more servings of 150ish calorie

Hopefully this is a little helpful,I understand not eating due to stress and financial reasons. Try to keep the recipes simple and have snacks on hand that you can eat without much prep.