Is it possible to tell whether you have acute kidney failure from symptoms alone(e.g. no urine, arrhythmia, hypotension, kidney pain)? should i stop all meds or just nsaid? can rehydration reverse the damage from acute kidney failure?

Depends on the cause. Rehydration will reverse acute renal failure secondary to dehydration and may alleviate toxin produced renal failures/ Please see a doctor in person for definitive diagnosis. You will need a good history and physical, labs and possibly imaging.

If you suspect acute Kidney failure you must see a nephrologist or go to the ER right away. First we have to see if that is what you have and why. That will decide the reversibility. Stop the nsaid. Good luck.