A lot of reasons are posted above with different explanations about why bitcoin price is dropping now. For me, I will hold my bitcoin now because there is a high chance of possibility that it will increase again base on the graphs I saw posted everywhere. Besides selling your bitcoin will not give you profit because of the very low price now. Just hold and believe that it will recover again.
it will take some time and for sure many of the weak hands will sell their holdings, for those reason behind the only thing that I believe is bitcoin and those quality cryptos inside the market will rise back so better to keep calm and hold your investment.