> For now I make a chicken sandwich for lunch, take like 5-10 minutes, fills me up, what do I do as a vegetarian.

Sandwich with hummus, tomato, cheese, lettuce. Very quick and filling. Maybe have it with a hardboiled egg. That's what I would do.

For a 20-30m thing I like to do asparagus, mushrooms, and tofu as a stir fry, lots of protein in that.

Since you mentioned a whey shake I'm guessing you get a lot of exercise. That's probably why it's more difficult for you. Plenty of people work out and are vegetarian, but yeah, both factors are going to make it more challenging and require you to be more mindful.

To be clear, I'm responding because I think it's an interesting topic of conversation, I think being a vegetarian every other day is a perfectly reasonable choice.