If you want to earn so much, then you have to have a very long patience. There is no easy money today, even in crypto world, you have to wait.
Unfortunately, today's situation on the market requires from us to be patient. If you are nervous and start to panic, you can make the greatest mistake - sell your coins. When the market will go up, you will regret.
No, I do not think sell to take loss always make you feel regret in the future. Sometimes, you must accept your mistake to keep safe your capital for investment. Do you see many cryptocurrencies dump so much value from the highest price since earlier this year? Example: ETH from $1400 to $400 (-70%), Bitcoin from $15,000 to $6,000 (-50%).