Dr. Clark gives a recipe to people who can't take the full dose at one time. I would say that you may be killing things up in the area that hurts. Try to take Dr. Clarks parasite program for sensitive people. I would not stop taking the parasite stuff all together, No, No. It sounds like you need it badly.
Try this and see if it works out for you
Herbal Parasite Killing Program
Flatworms, roundworms, protozoa, even bacteria and viruses are remarkably easy to kill using a combination of zapping and this herbal program. Thus it is not just for cancer, but a general treatment that can benefit almost every illness.
Hull Tincture Extra Strength (see the Recipes chapter, page 543):
Day 1: (this is the day you begin; start the same day you receive it)
Take one drop. Put it in 1/2 cup of water. Sip it on an empty
stomach such as before a meal.
Day 2: Take 2 drops in l/2 cup water same as above.
Day 3: Take 3 drops in l/2 cup water same as above.
Day 4: Take 4 drops in l/2 cup water same as above.
Day 5: Take S drops in l/2 cup water same as above.
Day 6: Take 2 tsp., all together in 1/4 cup water.
Sip it, don't gulp it. Get it down within 15 minutes.
(If you are over 150 pounds, take 2 1/2 tsp.
Do not take more than 3 tsp. because no additional
value has been observed.)
This dose kills any remaining stages throughout the body, including the bowel contents, a location unreachable by electric current. The alcohol in the tincture can make you slightly woozy for several minutes. Simply stay seated until you are comfortable again. You may put the tincture in lukewarm water to help evaporate some of the alcohol, but do not use hot water because that may damage its parasiticide power. Then take niacinamide 500 mg to counteract the toxicity of the alcohol. You could also feel a slight nausea for a few minutes. Walk in the fresh air or simply rest until it passes. You may add more water or honey or a spice to make it more palatable.