Other bathrooms are available. Your Tesla should be able to stop at those; it doesn't only stop at superchargers. One-mile-per-minute definitely sounds like so

Other bathrooms are available. Your Tesla should be able to stop at those; it doesn't only stop at superchargers. One-mile-per-minute definitely sounds like something was wrong. Did you try other charging stations? How full was your battery at that point? If you've seen that with multiple stations when you battery was neither nearly empty or nearly full, I'd suggest getting the car serviced as that's not normal behaviour.