I have watched my portfolio go down and further down. From my past experience, anytime I sold a coin, it shoots up in folds and as a result I have decided not to sell any of my coins. My portfolio is currently bad but I’m still holding, a better day will surely come
I hope that is the case but there are instances when a better day doesn't come(like what happens to most of the shitcoins out there). Just hold only when you think your coins still has potential to reach the price you want to sell into but if not, just find a good exit point and you will be fine.
But the whales make the speculation becomes more difficult to predict. Whales always try to make holders worry about that.
If holder really believes in the long term process then he wouldn't be fazed even if whales frequently manipulates what they hold, in fact it might become a blessing to them in the end of the day as whales sometimes creates good sell points.