This may cause another panic sell and price of btc may drop again?
I'm afraid so.However, have faith in BTC.
The price will eventually get stable.
IDK if this was a DoS attack or not, but I saw a reddit post the other day, titled, "The latest Mt. Gox DDOS may have been a turning point. The attacker lost money."
The upshot is that the attackers make money because the (D)DoS makes people panic. If we don't panic, eventually it becomes unprofitable for them to do it, so they might stop.
Article: Have We Reached A Turning Point For Bitcoin Exchange DDoS?
Reddit discussion