Since she's been in the hospital so long, you're likely back to Square 1 (when I was a toddler, I had to spend a few days in the hospital... they put me back on diapers, bottles, etc.... my mom had to totally retrain me). I'd go easy if she's still feeling unwell. Whiny is totally understandable when you've been ill (and had operations!).

Don't stop with rules though. Just go easier on the time outs (did you ever try making a fairy glitter jar?) when it comes to things that you know just means she's not feeling good... and definitely use this as an opportunity to NOT spank her at all.