I Have Been Experiencing Anal Bleeding (complete With Blood Clots

I have been experiencing anal bleeding (complete with blood clots at least quarter-sized) a few days before my period every month for the past year. I have been experiencing nausea regularly and sharp pain under my right ribcage (around where the gal bladder is) for about the same amount of time. all tests have determined the gal bladder is fine but the tests did show I have polycystic kidney disease, which apparently, should not be causing the pain, nausea, or bleeding. The doctors j have seen keep giving me the "everything seems normal, we can't find anything wrong" and send me on my way without my feeling any better. on the contrary, things have been feeling worse buy doctors don't seem as concerned as I am. Do you gave any ideas what could be causing the monthly rectal bleeding, sharp abdominal pains, and extreme nausea? Thank you!