After a very choppy morning, the bears took control and pulled price down with a vengence. Looking at a 15min chart (24H data), we pulled back to the 0.618 level (891). See chart below. The fact that the 50% didn't hold makes me weary of a rally. This 618 level hasn't broken hard enough for me to completely dismiss the possiblity. However, at the moment, I'm bear minded till proven otherwise. If we rally, the initial target is at 922.75. I also have a Gann level at 922, which could provide more resistance if we get there.

As a first indicator, I am going to watch to see if this 893.25 holds and the down trend continues. This is also a Gann level (see final image below)

If that 618 level fails, the next pullback is at 899. Which is very close to a Gann level at 899.25 (see final image below).
UPDATE: After falling further overnight, this 50% retracement turned into 897.75. We only got to 897.25, before falling of 6 points!

My homework study gives us these levels. This lists the Gann levels mentioned above.
Homework