I think it's important to have realistic expectations -- if your dates are correct, and you aren't quite 5 weeks yet, you will not hear or see a HB tomorrow. The HB starts around 6 weeks, and it's pretty rare to see a HB before 6 weeks (even a day or two before).
I think if you keep this in mind, knowing that you'll probably just see a sac at this point, then that will hopefully help with your anxiety.
I don't recall any questions that I felt as though I needed to have answered at 5 weeks. Are there any medications that you'd like to ask about? You can also ask when your next appointment will be and what they will be doing (u/s or just an exam).