Here is my genuine answer to your question. You should continue to hold your bitcoin even if the bitcoin price is starting to drop base on your observation. If you are asking why, then the best answer to it is because bitcoin price is not yet at it's peak meaning there is still a room for the bitcoin price to increase.

Decrease is only natural as it is how the market works but if you think that buying the promising stocks will surely to give you a good amount of profit rather than holding your bitcoins then you should sell your bitcoin right away and proceed in buying the stocks that you consider as promising but make sure that you will not regret your decision in the end so think twice before making a decision.