Hello Mathew
Welcome to HealthcareMagic.I truly understand your worry, it is indeed very unpleasant when people around you come up with such things about you. Common causes of bad odour is having a fungal infections, certain deficiencies like zinc,
vitamin C,
scurvy. Any gastrointestinal abnormality, if you are on certain strong medications. Certain infections like
typhoid,
urinary tract infection also might give a bad body odour. Again it is also dependant on your food habit-like too much of garlic intake.Now if you strongly feel, that you do have a price fishy odour, then it is though not very common, seen in a metabolic disorder called
Trimethylaminuria.It is an enzyme defect, which leads to accumulation of trimethlalamine and released through sweat, urine, breath, and other genital secretions, which gives this typical fishy odour.But before drawing conclusions, you need to consult a physician, discuss your complaints, well in detail, so that he guides you in proper way, about the line of investigations you need to undergo.So i suggest you to visit a physician soon.Take care.