I agree with the previous replies. Cutting off damaged hair while taking good care of your hair allows the new hair to grow in healthy and stay healthy. I know it can be a frustrating process, but hair grow back. I had extremely damaged hair just a few years ago and decided to cut it into a curly bob and take care if it so it grew in better. And it did. Now my hair is both long and healthy. More hair isn't necessarily better if it's in really bad shape.
I can't overemphasize how important protein is for damaged hair. Even if your hair is just high porosity naturally (which it might be) the protein helps to fill in some of the spaces in the hair and helps the moisture retain better. Some people just need lots of protein and lots of moisture for their hair to look and feel its best.