Site seems to already be back on, I wouldn't go to fretting unless their domain redirected someplace else, their support wasn't responding for days, twitter shutdown, etc. Something like this (site going down) is going to happen in the world of crypto which has an insane amount of hype with it right now, so this is normal and is going to happen -- people just have to get used to it and breath a little. It's understandable to fret about your cash, but we're all good here!