"Remember that the stock market is a manic depressive." (Warren Buffett)
Rules of logic often don't apply SHORT-TERM in investment markets. The well-known advocate of value investing, Benjamin Graham, coined the term "Mr. Market! (in 1949) as a metaphor to explain the stock market.
Sometimes Mr. Market sets sensible share prices based on economic and business developments. At other times he is emotionally unstable, swinging from euphoria to pessimism. But not only is Mr. Market highly unstable, he is also highly seductive - sucking investors in during the good times with dreams of riches and spitting them out during the bad times when all hope seems lost. Investors need to recognise this.
Another famous quote (Reminder) from Ben Graham: "In the short run, the market is a voting machine but in the long run it is a weighing machine"...