What Causes Foul Smelling Urine?

I am currently on microgynon 30 tablets to control irregular periods and mood swings and have been taking them only since Wednesday. I first noticed this morning that my pee has a strong, foul fishy kind of scent to it and I'm extremely worried about people noticing and the smell staying on me... I'm not sure whether this has been cause by the microgynon tablets or not. Advice?