bowels are strange, the same thing doesn't work for everyone. here are some suggestions and questions.
are you taking enough probiotics?
are you getting enough fiber? personally i like fresh ground flax seeds, they are far superior to psyllium in my experience.
have you done some liver flushing? this frees up bile which is critical for good digestion.
are you taking any digestive enzymes? when i get backed up i will take 15 - 25 tabs a day. this is what dr. kelley prescibed for his patients and he had great results with it. i buy mne from swanson vitamins, 300 tabs for $10.
are you getting enough magnesium and calcium everyday? this too is critical. i do moreless' alkalizing drink for my cal/mag needs and it works great for me.