I did something similar today - looked at my watch for the date and read it out: the 11th of March. The person next to me said, "Nooo... it's the tenth". Ah! But my watch says it's the 11th! Just ot make sure, though, I checked my phone date, checked the date on the computer, and looked at the date on their watch... all said the 10th. "I've lost a day!" I thought... but no, I'd just forgotten to reset my watch date after Feb. 29th, which means I've gone 10 days thinking it's the day after.