Why am I having heavy periods after changing birth control pills?

Hello doctor,

I have been on birth control for more than two years. I was on the combined hormone pill for the first two years and had my period every three months. Around the halfway mark, I began to experience breakthrough bleeding. I always had light clotting during my periods and never had breakthrough bleeding before. Finally, about a week and two days ago, I started a new birth control. With this one, I will have my period every month again. After finishing my last pack and having my period, I began them. It is now a week and two days in, and today, I started getting heavy blood flow and have had six large-sized blood clots. Is this because of my new birth control? It has been nonstop all day. I also have been researching endometriosis because I have pain after, sometimes during, sex. I also experience painful periods and heavy menstrual cycles, even when on birth control. I am also anemic. I am currently on Lessina but was earlier taking Jolessa. Please help.

Thank you.