I had the same problem as you with my nails. All I did was bite on them every chance I got and I thought I would never have long healthy nails. One day a friend of mine introduced me to Nailtiques
www.naitiques.com the protein is not expensive at all and it REALLY WORKS for all types of nail problems. I did the nail protein #2 everyday for the first week and then every other day after that. Once you get your nails where they are strong and growing then you would switch to nail protein #1 for maitianence. Anyway nothing else would work for my nails except for this product. Another little trick I learned along the way. Be sure and paint your nails a bright color like orange or red just to make them stand out. For some reason when your nails are painted you are most likely not going to bite on them as much or at all. Good luck hopes this helps you. Also use a cuticle oil and a good hand cream this will help too.