That was very bad time for me, when i sold out my Bitcoin. When bitcoin price was 9k+ usd, then i sold out my all Holding Satoshi for my personal problem. But now current price of per Bitcoin is 41k+ usd.
Don't be regret because you can invest again if you want. No body knows exactly what will be the value of bitcoin every single minute because it was too volatile. Now, it proved how valuable bitcoin is, it's really amazing this year 2021 that reached $40K above and always has a chance to increase more.