No, it's not that they feel worse - some heavy infestations just take time to remove - more than one cleanse.
HUMAWORM is just like any other drug - it contains chemicals that do various jobs in the body. An X amount of these chemicals can only remove an X amount of parasites, toxins, etc. For folks with very old, very well-established infections - it will take more than one cleanse to get rid of ALL their parasites and toxins. For most folks, however, the first cleanse will usually do the job and from then on - regular twice per year cleansing will keep the parasites gone.