I guess we will see everything fall and bitcoin rise 
I dont think it will drop below 400 in the next 8 months.
It is not smart to sell everything at once because the value of the Bitcoin can always go up again, that means that you still can make more money. I dont think it will drop below 400 in the next 8 months.But if you have just sold them all then it is not possible, you should always save some instead.
I think depends on the scenario. We all know that in bitcoin price fluctution, there is this cases where spike is extremely too high then after several hours it go back to its normal price. So i think if we seen this kind of scenario happening, it is right to sell all your coins then buy back at the normal price.