Our daughter (3 1/2 now) was under GA for about 7 times between age seven months until age 2. She had sleeping issues afterwards every single time. The first week was the worst but she had problems for about three/four weeks afterwards. At first we thought that it was because of the stress dose of steroids she got when she was under GA but the last times she was not on steroids and had the same sleeping issues after a GA for a few weeks. In the hospital I was up with her a lot at nights while all the other children were sound asleep. She was not in any pain just restless.
My son (3 1/2 too) has been under GA too a few times and had no sleeping problems afterwards at all.
I hope that the sleeping issues with your baby will disappear soon !