Hello dear, Thank you for your contact to health care magic. I read and understand your concern. I am Dr Arun Tank answering your concern. It is a hypotension that has caused you make this. Nothing to worry. It is common in some operative patients. As during the operation our body system becomes somewhat weak. So when you remain standing for prolong period or you can stand after prolong sitting such episode can occur. But it is nothing to worry in single such episode. But if it recurr on second or third time than you have to check your blood pressure. Taking a appropriate treatment can cure your such a attack. Please take enough sleep and forget the episode that has occurred with you. This will help cure your problems. I will be happy to answer your further concern on bit.ly/DrArun. Thank you, Dr Arun Tank Infectious diseases specialist, HCM.