If I am given a chance to go back to 2020 I would hold my ETH very tight and never let go, when covid was hitting the world at its best I thought it over and I sold 24 ETH which I bought at 120$ each, I never knew I was so damn lucky to buy at that price, learn to hold tight if you believe in a project, there are countless of projects in past years that are way bigger in value right now.
You are not alone. A lot has been regretting too that they end up selling their ETH when the price was quite low, not knowing that its value will go even higher this year. But not for ETH only, because i had also regrets that i was not able to buy more bitcoin and hold them more when there was a big opportunity to buy. Now i've learned my lesson, so i'm giving much importance to bitcoin right now, and to all the projects i have high hopes to be more valuable in the future.