Things like this are certainly hard to get, most people immediately sell when they get 5x or 10x profits, I also regret selling a lot of bitcoin and ethereum in 2018 when the market dropped.
For the pioneers, this is really happening. Like in bitcoin, ethereum, and other altcoins have risen dramatically and the person has been holding it for a long time and didn't sell a lot until the rise has been seen. It is not only you that regret selling those at early stages because even me and for sure many have the same story as you. But if you happen to sell that because you've got a valid reason, you don't have to feel regret about it. We can still have the chance to correct that mistake and if we're sure that the price of those will rise then we only have to do a few things, to buy at dip and hold.