Currently I own a lot of altcoin, I bought them at ico. My account is being downgraded several times. There are many people who say bitcoin will continue to decrease, so altcoin prices also decreased compared to USDT. So now, should I sell them and wait for the price to buy back? Give me advice 
You should take a look at the new altcoins that are traded on the Binance exchange, for example, a project like COTI is developing very quickly, and the price now allows you to invest from $ 100 by buying 10,000 coins that can be sold next year, I'm sure, at the price of 1 dollar for one token.