If you feel satisfy with your profit, keep go on sell your coin, but if you have one coin, you should choose another coin as your budget, at least 3 coins, it means when one coin down in price, another coin will help your loss if another had green arrow.
The market today has left many investors nervous and pondered, probably because many people have given up altcoin prices are falling, some people expect them to rise again. Personally, I'm sure they will rise again in the future.