Ultrasound Shows Cholelithiasis. Elevated Liver Enzymes. Worried About Liver

I am a 25 year old male Caucasian. I had an ultrasound about 7 days ago to check on gallstones which were originally found 4 or 5 years ago. The ultrasound showed Cholelithiasis is demonstrated , Incidental adenomyomatosis of the gallbladder . and Borderline hepatomegaly . . The report also says The liver is at the upper limit of normal for size, right lobe measuring 15.5cm. The liver is smooth in outline and homogenous in echotexture with a normal echo pattern. No focal hepatic mass. No splenomegaly . No ascites . . Also, my liver enzymes WERE elevated around 4 Oct 2012 (AST 40 U/L, ALT 77 U/L and GGT 72 U/L) and on 3 Dec 2012 mostly back in normal range except for GGT (AST 25 U/L, ALT 35 U/L, GGT 65 U/L). I do not drink and have only had a total of two or three standard drinks in total during my lifetime. Recent STD check showed no Hepatitis STDs. Additional possibly useful info: I weighed 85 to 87 kg around March 2012 (note I was not muscular by any means), between May and July I got my weight down (intentionally with a low calorie and low/almost zero carb diet) to 68kg and have been around 68 to 70 kg since that time. I am worried about my liver. What could be wrong, if anything? What follow up tests should I now get done? My G.P. seemed uninterested and more concerned about seeing more patients he can bill.