I bought some bitcoin in March 2017, sell half of it in Dec 2017 and hodl the other half since then. The current downward trend seem to last for a very long time and I'm quite upset about it. What do you guys think? Should I hodl or sell all my BTC now?
I recommend holding it until you feel the price that makes you happy. Once you've sold, you will be hard pressed to buy again because you always feel the price is too high. You did so well in 2017, so wait until the end of 2018.