Well it depends how long it was ago. But if she is still recovering, yes. Her body is still healing and she will be very sore, so it's natural to want to rest. It's just the same as if you went in for big surgery, you'd probably feel pretty rubbish and tired afterwards for a while.
Some rabbits seem to bounce back very quickly, but that is because rabbits hide pain, weakness and illness because they are prey animals. A spay is quite an invasive surgery, so it takes a couple of weeks to recover.