Alternate coins always fall while Bitcoin is going down. I think that in these moments we must be very patient. Indeed, after a fall, growth begins.
Bitcoin has always been the strongest factor affecting the market, this is because almost all altcoins are traded with bitcoin, when bitcoin vs fiat drops it automatically the altcoins value also drops.
This situation will never change. Bitcoin will be always the market leader, and the altcoins will follow their King. As for the dips, this time can be used for buying alts and BTC. You will spend on crypto less.