Fingernails are a product of protein and some of the fats in your blood. That is, if you're low on those things, your nails will start to fall apart on you. Check how you're using your points. Make sure you're getting adequate protein, and make sure you're adding some healthy fats to your diet. A 0% fat diet is NOT HEALTHY. Add some olive oil, some nuts, some nut butters, a bit of avocado, that sort of thing. You've done all the steps from the outside, now try from the inside.