It is my understanding that the toxins produced by the die off of parasites can make you feel worse before better. I myself in the beginning would get small itchy bumps about an hour and half after taking a dose of dewormer. THen they would go away as fast as it came. I also have been dealing with fatigue and headache.
It is also my understanding that many parasites are so small that you cannot see them in the stool. Maybe if you break it up to look? (if you want to go there :).
I have been seeing thread like stuff and white bits that look like rice but nothing that looks horrific.