2 days of bilateral flank pain that's off & on, smelly urine, and nausea. should i go to the er or wait till morning to get appt? drink more water?

ER: Go immediately to the er. Sounds like infection from either pyelonephritis, kidney stones , or some other cause but waiting too long and increasing the infection may lead to urosepsis which can be very serious.

See answer: Your symptoms are very suggestive of a uti/kidney infection (pyelonephritis) where usual symptoms are fever, chills, flank/back pain, nausea/vomiting, and possible associated bladder symptoms. If you are not running a fever >101, having severe vomiting, and able to push oral fluids (water) you can likely wait until am to get evaluated and treated which should not be deferred or delayed.