Just now drunk water filled in petrol can? urgent ? help me?

my office boy mistakenly gave me a water in a petrol filling bottle. we used to fil petrol in that bottle. he mistakenly put water in that and gave me. i drunk a little bit then i understood. its a bottle where we used to keep petrol in that. what to do now? i spitted water out but stil i feel irritation from lips to throat and petrol smell comes from my mouth and like acidity feeling? what to do suggest me very urgent.