Stress tests aren't supposed to be pleasant, not in the least bit. If it was pleasant, then you are one lucky guy. But in no way should we even come close to expecting a stress test to be nice.
Don't let yourself get freaked out over something that is supposed to happen. It's not like the game will be unplayable. People who pre-purchase didn't pay to play the game without any problems. ArenaNet intended to let people into the servers so they could test the game and get rid of bugs. That's what betas are for. No need to worry about anything regarding the game.
Also, be happy. Some people couldn't even get the client to run, like myself. I tried so many different things to try to get the client to run, yet nothing happened. Because of this, ArenaNet got over 150 client error reports from me last night.
Mixter Yosei Hecate
Bona Dea Ubume