yeah red blood isnt usually anything. the damage from drinking would occur in your stomach, and bleeding there either causes blood in vomit, or black stool. Red blood usually means something is up somewhere around your anus. The most common cause is Hemmeroids, which is what im willing to bet on this being. Still, if it gets worse, or keeps on for more than a few weeks, see a doctor. Also, if you spend more than a few minutes on the toilet to take a crap, dont. Sitting on the toilet for long periods of time promotes hemmeroids. Hit the toilet only when you need to go, dont camp out waiting for it to come.