Hi @safwenrekik, the value of your account is based on a 7 day average of the price of Steem.
Recently we saw the implementation of hard fork 19 which delivered increased payouts to newer users and those who did not already hold a large stake.
As a result of this, I believe those at the lower end of the scale have cashed out these increased payouts leading to a decline in the value of Steem.
There's more of it finding its way into the market and so the price goes down. It's going to take a while before it stops.
If you're here for the long haul then this kind of price adjustment/volatility shouldn't be an issue.
Thx 🤔😊