Well remember, SOMEONE is effectively shorting the futures NOW, this is bc when they were created it's unlikely the futures exchange(s) went out and purchased enough bitcoin to sell to buyers.  So the big exchanges might actually be net-shorting bitcoin just to sell the contracts.  Also, big banks may have recieved authorization from financial regulatory bodies to "naked" short bitcoin futures.  Regulating bodies have their own best interest at hearts (contrary to their official-sounding names) and might be working in concert to suppress bitcoin prices for the near future.  This was all documented by some gold-bugs back in 2011 when gold and silver were going "nuts". 
you can search the internets for more info on that.  

Main point:  with futures out there now, we all have to be careful about thinking the fast 100% up moves will last much longer, at least in BTC anyway.  Good time to be a little more "conservative" with bitcoin trading/investing.