What in the world was going on with Serena during the third round of the doubles tournament at Wimbledon? She had trouble picking up tennis balls during warmups. She looked wobbly when she walked. And eventually, her and her sister Venus had to withdraw from the tournament because Serena couldn't continue to play. She later said that she was sick, but ESPN commentators openly questioned whether or not she was on some kind of medication. It was certainly a strange situation.