1.First you need to find out what kind of infection do you have. Google your symptoms and signs of parasite very carefully. This is the hardest step. You can find out possible list of parasites you have.
2. Second step is to find out and buy drugs for those types of parasites.
3. Third step if to take them one by one and look which one reduce symptoms.
4. Take the drug which works and try to find out the doze and duration of treatment.