I suggest being really careful, let her seriously sweat, but DON'T let her know that it's bothering you. I repeat, if you declined meeting up with her later, give her a reason, even a fake reason... Remember, you are a busy man, and your not sitting at home pouting while she's out. Same thing with tomorrow, act like something else is seriously more important and urgent than her. Don't act like you are doing it in response to tonight. PLEASE. Just act like it's no big deal and do your own thang... Make her bend herself over to please your schedule and needs... Because I'm warning you, if you let her do as she pleases, she'll get tired of you.
NO MATTTER WHAT, don't let her know it gets to you, and let her know that your schedule and needs are no. 1 in your book THROUGH YOUR ACTIONS. good luck. ~Zappa