Bringing lunch on the go: vegan and gluten free. Ideas?!

Hello everyone,

I have been a vegetarian for 3 years and have since then also avoided eggs and reduced dairy as much as possible.

I've had skin issues (eczema) my whole life, but this spring it has gotten out of hand.

Since nothing showed in an allergy test, the only solution I can think of is to change my diet. (I have literally tried everything else.)

So, I read that an anti inflammatory diet could help, and I'll really try anything at this point. Since I'm already vegetarian, it basically comes down to a vegan and gluten free diet.

But what am I supposed to bring for lunch? I go to uni and the cafeteria does not have any vegan or gluten free options (let alone both vegan and gluten free, my country is surprisingly horrible with this), and I don't have an option to use a fridge. I used to bring bread with a meat substitute because it is quick to make and doesn't go bad when it sits in your bag all day. I have tried salads before, but by the time lunch rolled around the lettuce had gone all brown and it was just all soggy and gross. I love avocado, but that goes bad too. Nuts and fruits are obviously good, but I'm not sure I can fill up on that, especially since I usually only have ten minutes to eat lunch, so it has to be quick and filling. Does anyone have any ideas?