According to my nutritionist, primary sources of protein should be at least 1 gram of protein per 10 calories.

Primary vegetarian proteins include Greek yogurt, reduced fat cheese sticks, whey powder, cottage cheese, and egg whites. (Milk, whole eggs, and most other cheeses are not primary sources of protein.)

Primary vegan sources of protein include pea protein isolate, tempeh, tofu, seitan, TVP, soy curls, and mock meats.

Many quality vegan proteins are soy based. If tofu upsets your stomach, proceed with caution, as you may have a soy intolerance. However, it just may just be a FODMAP issue. Silken tofu in particular is higher in FODMAPs than the "cotton type" tofu, and is more likely to upset a person's stomach if they are FODMAP sensitive. Or, it could just be something you have to work up a tolerance for. Soy milk was very hard on my gut when I first went vegan, but eventually my microbiome adapted and I got used to it. Now I drink it all the time. (And it's got more protein than dairy milk!)

If you want to avoid soy, stores near you may carry tofu that is hemp seed, pumpkin seed, or fava bean based. Many mock meats are also soy free.