Green peppers can be hard on your system (they are unripe fruits) - you might want to try the milder yellow, orange, or red peppers. All protocol. Also I couldn't eat celery until I bought organic. The pesticides residues may be upsetting your system too, like they did mine.
Cook up spinach and fresh mushrooms - they go really well in an omelette (either IP packet omelette with herbs, or real eggs & whites for dinner). You might enjoy veggies roasted in the oven with garlic and olive oil. That tends to take away any bitterness some people taste with fresh raw veggies. Zucchini can be sliced and lightly baked with cinnamon and cloves and nutmeg for an 'apple pie' sort of dessert, also don't forget rhubarb (especially good stewed with Strawberry Mio as your sweetener). Those two are veggies as dessert, yum.
Also eat half your veggies, then whatever you have made for a packet can go with the last half of the veg. That way it doesn't feel like you get to eat good stuff first, then are 'punished' with stuff you don't like for the last half of your meal. That was always my trick as a kid. Eat stuff you don't like first, then save your favorite flavours for the remaining part of the meal and end on a good note.
You can always chop and blend into the soups (I know, summer and soup ??!!)
Jenny38 said it - 1st week losses are not typical, and our body needs to catch up and start losing fat not water weight in the next few weeks. Don't forget to measure even on weeks when you don't lose, you may be shrinking, lol.