Backstory: I occasionally play saxophone in a jazz trio at a restaurant in town. I know many of the waitstaff and managers, but not well. One girl recently got hired to greet customers and seat them. Anyway, she gave me IOI's for a couple weeks, and it was common knowledge there was mutual attraction (thanks to a buddy in my trio). So I banter with her a bit ask her for her number a couple weeks ago. She gives it, and I text twice the next day to say hi and how's her day been. She just sends a text "hello". This was before I knew that it was generally bad to text message.

I wait 5 days and call her and leave her a voicemail asking when she was free to hang out. She calls me back the next day and I pick up. We chat for about 20 minutes, she wants to go out for coffee sometime, but she has to get to class, so I tell her I'd see her tonight at the restaurant and figure out when to meet up. IOI's throughout the night, and I chat with her a little more and she says she has finals the following week. I say, let's meet after finals then. Hugs and she leaves.

I give her a call two days ago and leave a brief voicemail asking her to call me back when she's free. She hasn't called back yet. What should I do? I'm worried I'm getting mild oneitis, so ideally I'd like to sarge again, but it's a Monday, and I have a ton of work to do for a meeting tomorrow. I think the one problem is that we didn't get to know each other on a personal level enough before getting the #, but it's a bit hard to do that while playing an instrument, and I didn't want to dilly-dally. Please advise, even if it's the usual stuff. And it seems that writing this out at least has helped mitigate my annoyance a bit.

TLDR: Girl seems into me, suggests to meet up, but doesn't return the last voicemail I left. What should I do?

Update: I left her another voicemail saying something like, "Hey, this is Sillymallard. Call me back or not, but I won't bother you after this." She texted me saying something like, "Thanks, but I have a lot going on in my life right now." I deleted her phone number. Oh well!