Tried Praziquantel for first time and feeling like heading towards Panic Attack

Tried Praziquantel for first time just a few hours ago and felt hungry at first, then very uncomfortable abdominal pain as if heading towards another panic attack (had those a few years ago whenever I drank cold water since I had very sensitive stomach!), also felt like vomiting.

What does this mean? Lots of parasites? Where are they located? It is so bad right now .... can't really do anything to distract myself from the discomfort :-(