Can my body fight 'flagyls'? parasite without the anti-biotics? my eldest son has it and i think i may have it.

No, need flagyl: What kind of infection? A few parasitic infections are treated with metronidazole (Flagyl). Mostly they will not clear up on their own or will take a long time, and some are dangerous. If Flagyl has been prescribed, your son should take it as instructed, and you should see a doctor to determine whether you also are infected. You can't assume you have it just because of symptoms.