It is most definitely working! Most don't usually see things because it gets digested as it dies, while MOST parasites are microscopic! I have read, and it was MY experience that most don't really start to see things until after the two week mark hit, so keep going!!
The other thing is, a lot of people go sifting through their poo to find the parasites. They are heavier then your poo so they are underneath it at the bottom of the toilette! I never went sifting, but I could see tiny hair like things coming out of mine ever so often and only once did I see a GIANT round worm in my poo and I have done humaworm twice, and will do it again in two months! Best of luck to you!!