Hello Ray of light,
I would look at the ingredients of your protein powder to determine whether it contains any bad ingredients not allowed on the diet. If its a whey protein powder, it is now allowed.
I would look at the yogurt to determine how much sugar is per serving. Greek yogurt contains the least of all yogurts, about 8-11g per serving. Regular yogurt contains much more, something like 17-25g of sugar per serving. Try to keep your daily intake of sugar below 25g a day if possible.