Go a week and then a bender?!

Wtf is wrong with me?? I can go for days, maybe a week and a half without even the thought of porn. Then all of a sudden an urge or two one day, but still fine and avoided. But if I go a couple days more after the urges start up again, I end up slipping into an all day pirn bender. Its so stupid and frustrating! Wtf is wrong with me :/