I went to https://bitcoinwisdom.com/markets/bitfinex/btcusd and looked at the chart for the 1w time interval and this drop looks like a healthy pullback. What do you think?
i totally agree with this and also i say as long as you are zooming out of the chart and looking at the price change for a much longer period than just a couple of weeks (one way is choosing 1w interval) you get a better feeling about what is happening with bitcoin price.
It's just strange that not all exchanges are at the same price yet. They are off quite a bit. One says $890 another says $880 and yobit had it at $986 but since yesterday I could not even get to that site anymore. 
having a couple of bucks difference is normal between top exchanges and also it is normal to see a huge difference between the top exchanges and those bad exchanges like yobit who nobody trades at. it is because they don't have any volume so the price never changes.