Question about Ortho Evra?

I have eben using Ortho evra on and off for about 3 years. For the past six months I have had breakthrough bleeding or spotting during the time I would normally ovulate I have mentioned this to my Gynecologist and she blew it off and said that it was normal. I am terrified that this form of BC is not working and that I am going to get pregnant again. I plan on having either the Essure procedure or a tubal ligation after the first of the year. My gynecologist has tried to talk me out of having the traditional tubal ligation done as if I will need weeks and weeks to recover ( I think it is because she makes more money doing Essure) . Has anyone else ever heard of or experienced breakthrough bleeding after using a method of birth control for several years?