People waste a lot of time going to doctors who are basically clueless about parasites. parasites come in many classes but this would be a nematode or possibly tape, though with tapes you usually see "white rice" in the stool which is the actually eggs (these are the only eggs that can be seen with the naked eye).
Best guess (and I underline guess) is that it could be schistosoma due to the unique shape of them. Do a google image search and see if that matches.