3 Days of Diarrhoea - And No Sign of An End

:( I have just come back from bali - we ate excellent food the whole time we were there. However, since wednesday I have had terrible diarrhoea - we initially thought that it must be something that I ate just hadn't agreed with me - or because I had had ice in a fruit drink the previous evening (i would guess that the ice would have been made from tap water and therefore not good). However, here I am back in the uk since thursday evening and still no sign of the diarrhoea letting up. I don't like to take medicine - but out of desperation I have taken 2 immodium - didn't help at all. I would have thought that if this had been caused by something I had eaten then it would have gone by now. Feel like I am being slightly melodramatic fuzzymonkey.Net. Would be much appreciated.