Firstly, was that volume all traded 'on market' ?? (no crossed trades etc)
If so, for me, it is potentially bullish at this point (possibly some form of the absorption process), but as usual the next bar will most likely offer a confirmation either way.
As you are watching the story unfold on a chart, always look to the next bar for confirmation of the previous one....and while the story makes sense and is understandable, all is usually well.....