I think I have gallstones but my blood tests came back normal. What else should I do?

Get an ultrasound. Unless there is an obstuction of your bile ducts, blood tests will not demonstrate whether or not you have gallstones. An ultrasound of the gallbladder should show gallstones. Often, a test called a hida scan is also done to watch how the galbladder empties.
It depends. If blood tests are ok, that is good because nothing is affecting you now, but if you are still concerned, you can get a sonogram of the abdomen for gallstones. Many are asymptomatic, and show temporary elevations in bilirubin if symptomatic (epigastric rught upper abdominal pain). Even so, low fat diet, etc. Should be done before surgery since it may be too soon. See your doctor to plan it out.