Plumbing situation: worse. We decided to call our landlord today, as only 3 of us were able to use the showers before sludgey water came back up the drain. My last roommate and I were obliged to bathe at a friend's house 45 minutes before church started.
As an added bonus, neither of our toilets work either. When we tried plunging one toilet, water came up into the other toilet and both showers. We don't think that's a good sign. Until the plumber comes and fixes everything, we'll just have to hold it or make friends with our neighbors.
Huzzah! Landlord just called to say the plumber will be here within the hour. Hopefully they will be able to fix it immediately upon arrival.
UPDATE: The plumber came, fixed the problem, (temporarily) and told us he thinks it's roots. Yay! That means the landlord has to pay for it. Which is good, because I'm perpetually broke these days.