That happens to everyone. You could start off with 1/4 teaspoon then work up to a whole teaspoon. And you need to drink MORE water. Psyllium bulks up in the intestines. So you really need to drink a ton of water for this to work. Otherwise the psyllium will harden up and do you no good. Take some psyllium and wet it and then let it dry, you will see what I mean, it is like concrete.
Also, many of find that when doing the p&b shakes we must accompany it with enemas , especially in the beginning while the body gets adjusted to higher fiber intake.
Also, it is important to take plenty of fatty acids and vitamin c along with magnesium all of which help you go. Fatty acids lubricate, vitamin c reduces inflammation in the gut and magnesium relaxes the muscles so your bowels moves more easily.
If you continue taking the p and b your body will become adjusted and then you will be fine. I was the most constipated person I have ever known sometimes going 9 days or more with out a movement. Now I go everyday, sometimes twice while on p&b shakes.
It is a process, a gradual process where we are correcting the mistakes we made. It does take time. And you must go easy.