Pack me a lunch (please!)

Budget friendly ideas are mostly going to be bulk cooking.

Make up a big pot of soup Sunday and portion individual servings (freeze some if you need to) - chili, tortilla soup, butternut squash soup, black bean soup, chicken/rice soup... lots of options. 

Use a crock pot to make pulled pork, a beef roast, you can even mass cook chicken breasts in there to save time. Again portion out servings so the are easy to grab and go.

Your need to limit fruits/veggies is... limiting. Are there specific items that give you discomfort? Surely it can't be ALL fruits/veggies?
A big salad loaded with raw veggies and a protein (tofu or grilled chicken) is my go-to at least 3 days a week. And fruit is such an easy, go-to snack that requires little or no prep. Apples, bananas, berries, grapes.

Other ideas:
String cheese
Hummus & veggies
Guacamole & veggies
Cottage cheese
Applesauce
Hard boiled eggs
Greek yogurt (for more protein than regular)
Oatmeal (not from a packet, you really just need quick cooking oats and hot water)
Sweet potato cubes (you'd have to pre-cook at home and heat up probably)

I do the soup idea a lot- make a big batch and freeze, but will be hard if you can't get to the microwave.  Chili works well too.

I also like to do a little "antipasto" plate-  sliced grilled chicken breast (1/2 is fine for me), a sliced pickle, sliced carrots/cucumber/radishes, and a few olives.  You could add almost any nibble to augment...

I love kale salads- I chop the kale and massage it with the dressing, then add the other stuff.  Letting it sit in the dressing until lunch softens it up. 

Nicoise salad:  hard boiled egg, steamed green beans, 1/2 can tuna, olives, lemon dressing

Cold meatballs with a dip of some sort (I've been making my own paleo mayo) and some cold grilled vegetables- works better if the meatballs have some spices added