go see the GI specialist. no reason to wait. its a bile issue, so maybe gallbladder, liver, or pancreas. xray is probably the most pointless scan they could have run. abdominal ultrasound, mri, or cat scan would have made a lot more sense.
Dont worry yourself though, it could be nothing. hell, it could be you picked up a parasite or something like that. but go to the specialist. GP know next to nothing about the digestive system.