You don't just have to eat yogurt all day for every meal, there are other things that you can eat for protein besides yogurt to change it up. Eventually you will get sick of eating yogurt all day for every meal. You can have some eggwhites in the morning with some whole wheat toast dry, with some jelly, have a shake later on for a snack, then for lunch have a peice of fish with some veggies or a peice of grilled chicken, if you don't want meat you can have some legumes, eat some lentils they are very high in protein, a can of tuna in water......there are many different things you can eat without having to worry about eating the same thing, remember the amount that you eat is also very important (portion control) don't over eat. As long as you eat every couple of hours you will be fine, when you don't eat every three hours or so you might find yourself starving and then next time you sit to eat you will eat too much. Just eat very clean and stay away from white flower (enriched products) eat whole grains if you have bread, stay away from fried foods. Check out this website and read a little.
http://www.whfoods.com/foodstoc.php