May Allah Taala forgive all your sins and make you like an innocent new born child, after the surgery. May Allah Taala give you shifaa and remove all the ailments. May Allah Taala increase your iman and keep you guided in the path of Righteousness.
My mom and my dad, are without gall bladders for almost 8years now. Alhamdulillah they don't have any problem. So don't worry too much. Insha Allah, the surgery would go smoothly.