Did she have her spay and sent home in the same day or was she kept overnight? It sounds to me like she is still in the recovery process from the anesthesia from the surgery. If she seems comfortable and is resting offer her food and water but if she refuses she just seems a little more time for recovery. As for discontinuing pain meds, that is really not a good idea. It's proven that relief of pain promoted quicker healing. She just needs a little more time to metabolize the anesthesia from her spay.
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