Blood in stool=see doctor. Not much room for questions there. The rectum (rectum? damn near killed him) is an area that does not heal easily, and due to the nature, it is prone to infections. I really can't comment more on that without knowing more, but SEE YOUR DR! Make a mental note, is your stool red and bloody, and/or black an tarry, let the DR know.
Constipation is common with a high protien diet. It's not pleasant to talk about. You are eating dense foods and, very little ruffage. Try to get more leafy greens in. There are many fiber supplements on the market, pills, powders, wafers, drinks. If you don't eat your greens and veggies, take them.
Good luck, take it easy.