I've been veggie 30+ years and must admit I love it. But still don't have it every day. Meat subs are not the only source of protein as has been pointed out, there's protein in most foods actually and we don't even need that much.
On a weekly basis what I tend to have for dinner is a mix of pasta dishes (creamy sauces also provide a good deal of protein, but also Quorn bolognese), stir fry (sometimes with Quorn pieces sometimes 'just' veggies - actual mushrooms also high in protein, or with tofu, protein also in egg noodles), casseroles (again either with quorn or 'just' veggies but that can include beans and pulses - also high in protein), soup (I'm a Scot our soups are quite hearty) which can be lentil, beans, peas etc based with cheese rolls so additional protein in cheese (also very tasty dipped in my tomato and basil soup). Occasionally will resort to a from freezer to oven meal which will often be Quorn (fillets, steaks, pies, fish less fingers) but also things like veggie tartlets or veg pie made with a cheese sauce, or frittata (eggs packed with protein AND iron for the poster with anaemia)
And I'm quite boring and limited in what I eat at home. If you're a good and adventurous cook there's tons more you can do.
I've read about people having problems with Quorn but then lots of people have intolerances to natural and healthy food - doesn't automatically mean it's unhealthy - if that were true that would mean milk, eggs, fish etc were unhealthy, they're not just some people can't eat some foods.
I went veggie for ethical reasons but found stomach issues I'd had all my life GREATLY improved and on the odd occasion - especially when I first turned veggie and didn't know certain foods contained some meat proteins and also idiots who "tricked" me into eating things eg cooked in lard, I ended up with horrendous upset stomach within a few hours. So I seem to be intolerant to meat (I seem to be ok with poultry and fish it seems to be red meat proteins set me off, no idea why).
But yes as with any diet all things in moderation.
For the anaemic poster - Quorn has never to my knowledge claimed to be a good source of iron and most veggies know that best sources of iron are eggs, milk, dark green veggies and also that you need to have vit c at same time to help absorb it. I hope the anaemia is sorted though, I had it bad when younger due to endo it does leave you feeling really rough - and I was a meat eater then!