If you think $8K is the peak, than why sell at $6k? as you will lose another $2K, huge amount to miss. At least you should sell maybe around $7800.
Your words mean, you are not sure whether bitcoin could reach $8K before it get corrected, I am not either.
My best prediction is bitcoin will continue to rise after segwit be activated, and keep going to reach more than $5k or $6K.
I guess, this rally will stop on November when segwit2x hard fork or chain split will happen, that's the time when people start to withdraw their funds to save it, before buy back maybe at $2200 but I am not sure if it can be less than $2K.
Segwit2x hard fork will definitely be a showstopper, if the rally even keeps going until then. I also assume that BTC will not get much lower than 2k, if even that. However I doubt that BTC can go much past 5k -- this time. But I'll happily be proven wrong.