same here though my investments are not that much compared to yours but my portfolio has dipped up to 70% of my original investment I've been waiting for the market to recover since.
What you did wrong is that, you invest in the market while the price is very high and now it was dumping and you are losing the value of your coin so you better hold your investments and do not even sell it.
He didn't do anything wrong actually. It was just normal thing for people to buy more and hold. Almost all people thought if bitcoin would be hit more than $25k back then and that's why they choose to buy more even bitcoin was on $19k. No one knows if bitcoin price will be keep going down after that.