Why is my nail polish falling off?

My nail polish is literally just falling off, like the whole nail. It doesn't gradually chip off, it starts to chip then just peals right off, so I wake up with one or two nails unpolished and find the polish later that day on the floor or in my bed. I don't know why it's happening or what I am doing to make this happen. I use a base coat and a good top coat but it still just falls off. Why is this happening and how can I prevent it?