According to you . if in the current time, what do you do when bitcoin decreases current price? do you sell or hold and buy bitcoin again?
and do you think that bitcoin prices will rise in the near future? give your opinion and your reasons whether bitcoin will rise or even drop drastically?
Take a look at May-July 2017. There was the same situation imo. Ofc it was caused by the 1 Aug fork, but still the market was corrected after so huge growth. And after that take a look what happened at Sep-Dec

Its true, we might be in for a similar period that we saw between September and December of 2017. Safest bet is to hold your investments.
If Bitcoin is coming down, at a certain point where you can see the resistance (buy support) it can be worth to slowly buy in, meaning buying more btc in small chunks as it nears the support.
I do not see Btc dropping drastically, will only happen if the crypto space completely abandons it and uses another cryptocurrency as its "gold standard" (to which it pegs its value).