I'm glad the OP found someone to help her. From what she's posted, it does sound like her friends were a little flaky--it sounds like they offered to help in that specific way on that specific day, in case the original plans fell through, and then when the original plans DID fall through only a couple days later, suddenly they were all busy. Which, on the surface, to me gives the impression that they weren't serious about their offers at all.
When people make much more general offers of help, though, I don't think they can be expected to drop their plans and assist whenever, whatever. A couple years ago a friend of mine had major surgery and needed weeks of recuperation time, when she had trouble getting around on her own. A lot of her friends had said, "Just let me know if you need any help!" Then she would call someone at 2pm on a weekday and ask them to drive to her house right then, from their work, and help her get into and out of the shower. And they'd say no, and she'd be disgusted with them and think they weren't being good friends. Granted, this is kind of extreme, but I'd never seen the situation from the other side until that incident.
But just to reiterate, I don't think the OP did anything rude at all in this situation.