I have had pinworm before and it caused extreme anal itching. I took Antibiotics for about 5 days and they all died. I also saw TONS of them in my bowel movements without Diarrhea or other symptoms.
This time, I think it is much much worse. I am seeing a specialist soon so he may be able to figure it out- but these worms looked much longer than the pinworms, probably double to triple their length.