Need some advice/help. I bought ATH and i’m stressed out

Like the title says I entered the crypto market in early November because I kept reading people saying that "time in the market > timing the market". So I basically bought 42.000 euros evenly divided in 4 coins (BTC, ETH, SOL and DOT).

In the mean time around December I converted my BTC into ETH and SOL into DOT and since then all I keep thinking is HODL but all I see is the value being chipped away at day by day.

Yesterday I had almost 55% loss so around 20.000 euros, today in just a few hours I'm at 17.000 euros.

What would you do in my shoes? Would you sell or what?..

PS: I still have an extra 18.000 euros on the side which I'm seriously thinking about what do do with? Buy the dip? but the dip keeps on dipping.. and are ETH and DOT still a viable coin in the future?