There is a reason. Putting into context today's price action with the parabolic price rise over the last year, it looks like a mere blink.
The vertical direction of the price was not sustainable. And when the market loses steam (and buyers), it needs to refuel both at lower prices. Looking closely at the market with low time frames, today will show only long red candles, which will directly switch on your panic mode. Take a step back, instead, and look at the big picture. One interesting aspect of this ramp-up since March is that we can assume it was fuelled mainly by spot buyers and non-speculative players. Overlapping to Bitcoin's price chart the number of short and long leveraged positions, you will see that Bitcoin is one step away from an all-time high despite the significant headwind of short positions building in parallel.
If that is not a positive insight per-se, consider that the risk of severe drops caused by long liquidation is not very high. The number of long positions is close to the lowest in 2020. On the contrary, a short-squeeze that would push the price higher is more likely, if the psychological mark of $20,000 breaks.
Bitcoin's price may be 10% lower today, but it could be actually closer to a new all-time high than it was yesterday.