Did you put anything up there that would make it bleed? You know those capsules are for taking orally, right?

j/k
joking aside, you should definitely see a doctor about that one. I have had that happen to me before because of my irritable bowl syndrome and severe milk allergies. For me it was nothing, but it may be a coincidence and could be anything from hemmeroids to cancer, so you definitely should get it checked out.
Btw my wife takes that same meds (10mg xr), she gets stomache aches and nausea on it, so maybe it's harsh on the stomache.