I think as of now you should buy lots of bitcoin because it still a small market value. The company of bitcoin will rise up once again before this year 2018 ends; lots of income will come.
if you still have bitcoin, I would just say do not sell and wait for the price to go higher because a lot of people will hold the coins nowadays. At that point what you should be doing is selling and not buying because of its high value, buying at that time will not be as good as I say wait time when prices fall