Welcome to Crypto.... Alts usually trade in a more exaggerated manner than BTC to start with.

When BTC is at ATHs, alts start to dip. Remember most alts are traded using BTC. If you invest in Alts then you're actually Shorting BTC because you assume they will perform better.

When BTC is diving Alts tend to dip again because of the fear of how far BTC will drop, hence bringing the Fiat Alt value down with it.

When BTC is stable and moving at a typical clip while NOT at ATH's is often when Alts will make their move.

So yeah, right now as BTC dives we're going to see most alts dive harder until BTC completes its correctional phase. Volatility is great for trading