120 g of protein is a great amount. If you are getting full, do not stuff yourself. There's no reason for that. If you want to add more protein, there are protein supplements: whey protein shakes and whatnot. That would get you an extra 24 g to 30 g of protein but if you're feeling full I wouldn't really worry about it too much. What happens often, but not always, is that people, when losing weight, are so used to eating a high-caloric meal that they feel hungry all the time, even being at a lower caloric density. By making sure that you focus on the protein, it will tend to keep you fuller longer. The fact that you are gaining 120 g of protein and it feels comfortable for you, I would stay with that. If you are finding that you are hungry then I would focus on getting some more protein in your body, if that makes sense.