Spotting after period ended

My period ended for five days and then I started spotting again. I’ve been spotting for two days now. I’ve been on birth control for three years now and this has never happened to me. I take it at the same time every day as well. Any ideas what could cause this? Should I worry? It’s pink/brown and I’m even getting some blood clots. It’s not enough to have to wear a tampon, but it is significant.