I would do a fecal (whips are awful and sneaky), urinalysis (the drinking), and hw/tick test (your location) if not run in the last 6-7 months. Then, if all that is good, and she's still not doing well - I'd personally skip an x-ray and ask for an ultrasound referral. My vets think I am nuts, but I am right enough times to make them wonder (stopped clock!).
I wish you and your girl the best.