Ok, personally for me....I would not be upset that they didn't do the spay today without the proper bloodwork in order. I would count it as a blessing and would have the outmost confidence in my vet...he/she was watching out for the well fare of my girl, instead of moving forward without the bloodwork.
I too, am glad all went well with the dental.
I am sorry you have to dwell on it for 2 more weeks, but know in your heart you are doing the best thing for your girl. In this world of technology we all know these things happen and your vet considered her well being first.
The part I don't agee with is not calling you to come and pick her up due to the delay.