It's going to take something nobody is expecting at a time when your shorts are at your ankles and you can't get to the computer fast enough to cover, add or just plain buy after watching for weeks or months.
The same thing happened today, as on most days. A 10% buy of the days volume is a serious chunk of shares, but 'they' see that and sell into it, and won't let you close 'green'. You can't get ahead of 'them' when they need your cash.