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 have to decide this. If you think that coin will not rise as you said it is bad, then sell it before the amount of your losses increase. But if you think that a coin has a potential of increasing and it is just due to some fall in demand then Ill suggest you to hold on. It can be due to the owners manipulation, in that case also Ill advise you to hold. But most of the times I have seen poor ICOs whose teams do not perform really face a very poor fate and many a times just go wasted. Have you heard of bitjob student coin? It lost 95% of its value after the ICO.