I still have a lot of Altcoins left in 2018 and I haven't decided to sell it. Because I also still suffered heavy losses. But this is at my risk when holding lots of coins. I will sell it when the market has gone up and now I'm sure the market will come back up again.
Much better to keep your coins inside your wallet while the bear season is not yet been over, many cases like you already suffer big loses after deciding to panic sell their asset when that big fall downfall happen few months ago, thinking that everything will collapse and avoid to lose bigger than what they've think of, suddenly a big mistake and for sure regrets are stressing them, market is moving up again and keeps trying to make a strong barrier.
Sell your coins if you already have a break even or you are cutting loses to catch up with another moving coins that you think will allow you to recover, the principle of buy low and sell high at this moment is really hard to achieve.