Does that yogurt Activia?, work?

I need to know if that yogurt works, because my whole life I've had constipation problems. But recently I noticed that I stoppped going poop. The last time I went was Jan. 14 and since then I have not gone. I've been walking a lot, eating oatmeal, prunes, Bene Fiber, stool softener, drinking water and eating fine. I've been doing what my doctor told me too but yet nothing. Is there something wrong with me?