My doctor is sending me in for a ultrasound of my gallbladder and liver should I be worried?

No. No, this is fairly routine testing for anyone with elevated liver labs or pain in this area. Your doctor is probably looking for signs of gallbladder problems like stones. The test itself is fast, mostly painless, and will give you a great deal of information.
Good Care. If you doctor feels you need an ultrasound he is likely following up on a complaint, symptom or lab abnormality during you visit. The test is painless and has no radiation exposure. It is an excellent first line test. You should be only concerned enough to follow through and find out the results and what prompted the examin in the first place.