T.W.
My younger daughter had her adenoids out, sinus cavities flushed and tubes put in. Honestly, she was better and playing 2 hours after the surgery. She was a little grumpy and she was on antibiotics for 10 days after. No side effects, the sinus wash is basically just spraying saline through the passages to clean everything out. We had great results and I am very glad we did the surgery.
My older daughter at almost 3 had her tonsils and adenoids out, sinus cavities flushed and tubes. The biggest difference between the two surgeries is that the tonsils was much more difficult and painful of a recovery. I think that she reacted negatively to the anesthesia, possibly a delayed allergic reaction? I don't know what they told you, but with the older the recovery room time before leaving was I think 3 1/2 hours. Bring something for you to do. She slept almost the entire time in recovery room and then they want you to give them a dose of medicine before they let you leave. The one she had was alcohol based, so she hated it b/c it burns. I think her recovery was about 2 full weeks, but again we had the tonsils out. After recovery the results were good and I am really happy that we did her surgery.
Good luck! Let me know if you want more specifics.