F.F.
I was mostly going to say what Heather said, but I wanted to add that at some point, and I don't remember exactly when this happens, your breasts do stop feeling full even when they have milk in them. That's because your body gets better at regulating how much milk it needs, so you may never feel full again except when you wait too long to nurse, but there will always be milk in there as long as you keep breastfeeding.
Also, just to second what Heather said about the milk. The first milk that always comes out is really thin and watery, and after the baby nurses for awhile it gets thicker and fattier. Both kinds of milk are perfectly normal and serve their purposes. I also want to add that milk is always evolving and adjusting. The milk you made for your newborn is different from the milk you're making now, which is different from the milk you would make 6 months from now. Not only that, but the milk you make at 7am is different from the milk you make at 7pm. Our milk is perfectly calibrated to our babies needs. So if it looks different from one time to another, that's why.
Keep it up! You're doing great. You do still have milk, and if you want to up your supply, all you have to do is nurse, nurse, nurse!