sever left pain and blood clots

36, tubal ligation 12 yrs. ago. periods worse since. But, am now having severe pain on left side before and during period, with medium to large blood clots.Bleeding and clots, pain so bad on first couple of days can't leave home.I do not wear tampons, because pain increases. Periods are irregular in last year. And have become longer. from 4 days to 7 or 8. Have had X-Rays, but, no pap test this year.