Not Feeling Full ????
I measure things out (1/2 cups worth) and find that if I don't rush, I finish my 4 oz, and soon after feel like if I'd had another bite it would have been too much. Sometimes I feel like I'm getting full while eating, only to notice that I'm not putting the fork down and have started to go back to shoveling the food in as fast as possible.
One thing I've noticed, if I eat something I really enjoy (especially tasty) I take my time with it more easily than if it's something quick and easy. Maybe this will bring out the inner "foodie" in me!
Good luck - remember volume and quality are premiums in this life - get your protein and keep the volume to 4 oz!