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 
I think selling all your investment right now will not give a lots of profits so if you want to manage your life using this income then selling 50% off your investment will be right here but you need to definitely hold some amount here then only it will grow and make your life better.