I recently went to the doctors for a toothache and they perscribed penicillin and oxycodone. About a week later I went to the restroom, and noticed blood in the toilet. It wasn't in the stool, it was from my rectum but without a bowel movement. I also drink alot of beer, I am concerned about the issue, could it be a result of the antibiotics and the pain killers, or from the beer?