i wouldn't stress about it so much if you know she's away on business you can't expect her to drop everything she's doing and call you she will when she will there's nothing you can really do about it that's the situation you kinda got yourself in by giving your number to her, important thing is to realize that's not always the best of moves but at the same time there's ten billion way more stupid things you could've done and it sounds as though she very well might be interested too so relax go out with your friends, meet new people because the whole point of all of this don't forget is to talk to as many women as possible if not to give yourself more options to give yourself practice in social situations, test your own negs, conversation topics, openers , etc. so whenever you do see this girl next your a little more seasoned

im sure she's very nice and all but you need the mindset that she is still just one girl of many on this planet and that SHE needs to prove herself to YOU too

and personally when she does call you back i woudln't answer right away, let it ring and go to voicemail and call her back a little later on so as to make it seem like you were doing something important and your not just sitting by the phone