Basically DE works by scratching the exoskeleton of bugs, parasites and worms which causes them to lose water. Ultimately they die from dehydration. Your symptoms lead me to believe you have A LOT of parasites.

I copied this from the website I linked below.
Diatomaceous earth (DE) is the remains of microscopic one-celled plants (phytoplankton) called diatoms that lived in the oceans and lakes that once covered the western part of the US and other parts of the world.

Just verify you are using FOOD GRADE diatomaceous earth. You could become very sick if you use the pool filter grade because I believe chemicals are added into it.

This website has a lot of information to look over.
http://wolfcreekranch1.tripod.com/defaq.html

Have you done any type of colon or parasite cleanses in the past? If not, then you are probably just getting die off symptoms. The first time I did a colon cleanse I felt absolutely terrible. Good luck!