STYLETHREAD -- LET'S TALK SHOP!

JMO - You are fine. Things happen, and it is okay to feel bad. But don't dwell on it. They should be thankful that they are being offered a fun weekend, and be willing to switch the date.

I would never be mad at a friend that had to cancel on me as long as it wasn't for something trivial (or to hang out with others, something better came along, etc.) I might be disappointed, but I would understand.

I feel like if she is a friend she should be understanding that things come up.  It's not like you are cancelling all together.  You are just moving it to a different weekend.  I personally don't see anything wrong with it.  Maybe she hasn't responded because she has been busy and hasn't see it yet.