Why after a year of using Evra patches are menstruation again more abundant?

The gynekoloszka told me that when I start using Evra patches, my periods will be less heavy and menstrual pains will be less, and so it was until then. In July it will be a year since I use the patches and the pains are again unbearable and the menstruation is so heavy that I have to replace the sanitary pad every hour. Why? It was good, why it changed again