long and irregular menstrual cycles

I am 33 yrs. old. I had my tubes tied at 24 yrs.old because I could not take birth control because it made me bleed constantly. My periods have been irregular since but in the last three years they have gotten to where I bleed 2 to 3 weeks out of a month and have severe cramping. I have been to a gynocologist and he has said that since I can't take birth control that there is nothing he can do. I would just like to here if these are symptoms of anything or if there might be some way to make it more regular.