Applying for Physics PhD program with strong application but weak test scores
First of all, congratulations on publishing and achieving that GPA! Together with strong letters that should make for a strong application, even with weaker GRE scores - maybe excepting places that use some kind of subject GRE score cutoff (if your score is too low). However, there's no such thing as guaranteed admissions for open applications like this. It'll depend on other applicants, your field, which research groups are looking for new students, etc.

The upshot here is that the GRE scores are easier to change than any other part of your application. Do all the practice tests, figure out tricks that work - dimensional analysis will take you far on the physics GRE, for example. You can also sit for the actual tests more than once, which might help with the stress levels.