My mum and sisters are veggie. In fact middle sister is a vegan so is very clued up about nutrition. They swear by veggie chilli with 5 varieties of beans in it, lentil soup or quinoa. These are all protein rich I believe.
I'm pretty sure wholegrain is protein rich so you could try replacing bread, pasta and rice with brown wholegrain varieties if you haven't already.
Don't forget about iron too. With meat eaters it's easy because meat contains iron and protein but you need to be a bit more conscious about iron intake I think if your veggie?
Should point out I'm not a veggie so apologies if I've got anything wrong. Having been bought up as a veggie I do eat a lot of vegetarian food and would recommend the Vegetarian Society for further advice. We used a lot of their cooking ideas and info when we were growing up.
Honestly I can't see how supplements will help you with protein. Especially when growing two babies. I would urge you to consider your diet because the early months are very important for baby's development.
Where do you get your protein normally? Do you eat eggs and cheese? Also rice with lentils? Other beans?
nuts are a good way to snack, or some bread with peanut butter, I'm also veggie, and try to make sure that everything I eat, whether snack or main meal has some protein in it. I also try and have some tofu every day, as it's very rich in protein, you can even fry it till it's crispy and put some soy sauce with it for flavour and eat as a snack, as well as with a main meal.
I eat loads of omelets and tofu when pregnant (and meat and fish) - I keep the local branch of Wasabi in business by eating loads of the sushis with sweet tofu on. Fried tofu is great stuff - crispy on the outside, creamy on the inside. Beans and wholemeal bread are good, also seeds to munch on.
I have some whey protein powder at home from my pre-pregnancy days. I'll check the ingredients when I get home later to see what vits it has in it... I think it will have vit a so won't be suitable but it's worth checking
I have checked the whey protein powder I have at home and there are no added vitamins as they are a diet supplement, not meal replacement. I can see anything in there that could be harmful but maybe check with your gp? I bought mine from my local gym (they specialise in bodybuilding and whey protein aids speedy muscle recovery following weight training). The great thing is they taste yummy and come in hundreds of different flavours! The one I have is a SCI-MX branded one.
I've heard that halloumi has got protein in. I'm having the same problem as you btw, I'm having twins also and really struggling with my diet. I've started eating nuts, beans and lentils. I have the beans for breakfast and lentils in a curry or a soup for tea or lunch. I think you should try not to worry to much and just try and make little changes as you go. I was ill with hypermesis until wk 14 (now I'm 18wks) so I'm trying not to force too much food on myself but just taking baby steps. I think it can be overwhelming to think that there's two litttle uns and you to keep healthy but you're only human and I think its fair to say you're not always going to be able to do evrything by the book. Thats what I've told myself anyway, I still panic every now and then but eating healthy and being happy and calm is paramount.