I can't speak for Europe, but here in the states stool tests are not a proven reliable way to identify parasites -- coming from someone who has fruitlessly gotten knocked around the medical system by inept and ignorant healthcare professionals.
My advice is: pursue the medical route if that's what you choose, but be proactive. Get in the driver's seat and start taking charge of your own health now. If you do some Curezone searches on the different forums, you will read about the hoards of people who have gotten little or nowhere from the healthcare system, so have your back-up plan prepared.
And in other searches, you will find loads of information about healing yourself and finding a protocol that works for you. Search and read, search and read. Then form your own opinions.
I'm not convinced drugs are the answer anyway. Changing the environment is where I think it's at.