Sounds like you need to repair the damage inadvertently done to your digestive tract, and then not do any more.
From what you say, it sounds like you need to not only nip the parasite issue in the bud, but Primarily get the elimination channels open and flowing down and out, so as to eliminate the parasite die off. Common sense tells says It doesnt help killing parasites within the bowel if they are not being flushed out with a daily bowel movement.
The key is to get the elimination organs working effectively, and this means the bowel as your priority. Several LBB 3-4 times per day has been known to assist even the most severe cases. You may find the post mentioned above to be most inspiring. An entirely natural and inexpensive may to get this sorted.