Deterioration of teeth enamel. My teeth?

I used to have very healthy teeth. No cavities no aches. Recently I am feeling that my teeth enamel is deteriorating very fast. The size of my teeth has become smaller. Sometimes I even have minor injuries on my gums when I chew something crispy due to smaller teeth. At few spots on molars I even have very high sensitivity. When a small hard particle of food is chewed and goes to that spot the pain is unbearable for a minute or so. In general my teeth have become more sensitive. I have already switched to sensodine toothpaste. Further, gaps in between my teeth is also increased. Leading to food particles, specially non veg, getting stuck and causing pain too. Please suggest what should I do? Is there any way to get up any sort of cosmetic surgery with which I can grow a layer on my teeth?