Yep, Steam is down (update: we're so back)
It's not just you: Steam is down right now. If this were a Tuesday around this time that'd be no big deal (Valve does maintenance every week), but on a Thursday, it's a cause for greater concern.
The store will sometimes load, but it's running very slowly if at all right now. According to SteamDB, over half a million people have checked in to see if the service is down, and I bet a good chunk of them are Counter-Strike 2 players wondering why their ranked match just imploded.
Even if you are able to login...