I have been on the same birth control for 3 years and recently i have been experiencing breakthrough bleeding. i went to my gyno and everything came back fine. but now its happening again. i never have unprotected sex and i don't miss pills. what is this

Breakthrough bleed: Breakthrough bleeding (bleeding at the wrong time) is very normal on birth control. It happens in about 1/3 of users. Its no big deal and usually self corrects over time. If you are not satisfied or it continues to happen then consider using a different birth control method. It is a common side effect and does not mean something is wrong or that the pill is not working.