I think its partly because there has always been upward...

I think its partly because there has always been upward momemtum. But the downward momentum was just stronger (shorts), for the past few weeks.

And that even though there was only 10+mil worth of shorts actually traded. That didn't include the possible shorts sitting on the book making the sell side look fat.

It's possible that when the buyers started pushing a few pips up, 3 things happened:

The shorts on the book were cancelled (removing the cap on the sell side).

The current shorters stop-loss triggered (making then buy back shares, causing more upward momentum).

And then the already pushing upward buyers took over, repeating the process/ cycle multiple times.

Remember to do your own research though. As my example is just on of many ways this could be why theres movement.