I joined an ico in january 2018 and it was a bad ico. The price of this ico is 1/6 of the ico price and i lost about 3000$ if i sell now. Someone can tell me what should i do? Sell or countinue Holding? 
You should already know that joining ICOs are for risk takers. Even in cryptocurrency trading, there are always risks and you have to be prepared. Its either a hit or miss, so we are 100% responsible on what we are investing. You are not alone, because there are others who were just like you that ends up in a bad project where the devs might ran off. Just my two satoshis.