It will be very difficult to dump the market further(it is possible, but it will be very difficult and dangerous), because the miners are already working at a loss on some coins, like ethereum. Bitcoin almost fell to mining cost price, so, i think, it worth to start to buy now.
Every year the same thing: as soon as the prices of cryptocurrencies fall, another "crypto preachers" appears and says that it is time to buy crypto.
Since the spring of 2018, there have been so many such preachers that at some point I even got tired of reading their calls to buy crypto currency, even saying probably not worth it that they were all wrong. His head to think when to buy and sell.