I am so happy to hear that Suzie is doing better. Big ((((hugs)))) to poor meowmie. I know all too well how scary this very situation is.
I had a very similar thing happen when my Hallie was spayed in 2003.
She was dropped off at 7AM, spay done by noon, all was supposedly well, pick her up by 7PM. Simple right? No way.
I was there at 7PM. The vet's office stalled me for an hour and a half, telling me she was still waking up. Finally at almost 9PM, they gave me my now "awake" cat, who was breathing, but not moving at all, eyes closed, face almost completely nose-down in her carrier. The vet told me that she had been an “anesthesia hound” (yes, that is an exact quote), and that she had required almost twice the normal dose of anesthesia. To this day, I am convinced that he almost killed her that day (and I soon switched vets after this incident).
Once home, I left her in her carrier, and it was 2AM before she moved at all. Over the next few hours she woke up a little bit, just enough to vomit twice. I took her out of the carrier to clean it, and she pathetically stumbled (falling over several times) the approximately 3 feet to her catbox, where she peed. She then stumbled another very sad few feet, collapsed, and passed out again for another ~6 hours. After that, she finally slowly woke up normally, and within 2 days was happily trying to rip out her stitches (she needed to wear a "cone" for 2 weeks) She recovered fine, and is still well today.
Diane (who is sorry for the hijack/epic post, but I can so totally sympathize)
Here is a photo I took of Hallie once she passed out that first night (I hope that it isn't too graphic - I couldn't figure out how to thumbnail it ):