If you like yogurt (I don't -- and I'm lactose intolerant anyway), try GREEK yogurt. It's low fat, super-high protein. In case you find it and think, "Whoa, that's more expensive," it's worth it due to the protein/ low fat combo.
Are you vegetarian? I'm confused since I always get MORE protein than I need. I drink 3C of soy milk a day (partially for the many nutrients but also for the phytoestrogens and MOSTLY for the healthy fats that lower my cholesterol). That boosts protein and then my lean meats and fishes are full of protein.
I don't eat cheeses and do eat nuts (too many cos I LOVE raw nuts!) but I don't eat them for protein. They're not the best source.
Can you eat legumes? I'm also a big bean/ pea eater. This week, I added aduki beans to my salads and roasted veg.
As far as "GF items," I've tried 1 kind of cookies and 2 kinds of crackers. Anything else, I've experimented with myself but NONE of them were clean-eating/ nutritious foods (basically baked goodies).
I'm trying to toss out all these things in case any of them help :)