Andrew, don't feel too bad. You did the right thing. Imagine you left her on the street and something unspeakable happened to her? I'm sure you wouldn't feel great about it. I think your only mistake was to take this entire endeavour so personally. Keep in mind you were dealing with a SP and you were paying for services. Sure you were pumped and excited but is it really unfathomable that this girl was a bit weird and the night didn't work out as you planned? This isn't a girl from church you finally asked out on a date. It reminds me when members come on the forums and absolutely blast an SP for standing them up and they take it like some kind of mortal wound. You need to keep everything in context.
Things could have been much worse. She could have been a crazy insane drunk, she could have crashed your car, or not even told you where she lived. Ultimately everyone got home safe and the worst thing that happened was you were disappointed and at the very worst, need to change your phone number.