Protein?

Hi. I am a vegetarian though I do eat salmon. A friend of mine said that to build muscle, you need protein and that I'm probably not getting enough since I don't eat meat. I'm pretty thin, but could tone up a bit (skin doesn't seem tight enough), would protein help tone up? And how can I get protein if I don't eat meat? I've been thinking about eating chicken again, but I can't seem to do it. I honestly don't want to. Thanks! Tweet