Oh, I know the feeling! When we leave it's always so difficult for me too. I just want to take our birds with us everywhere!
Before we got our conure, if I had to leave for a day or two, I'd just make sure my tiels had enough food and water and I usually put in a treat stick and left em. But since we got our conure there is NO WAY I can do that because he needs his waters changed like 3 times a day! He's such a pig. So now I absolutely have to resort to a sitter, even for over nighters.
Lucky for me, my daughter is 18 and a GREAT house sitter so for now, my trips are covered but in years to come??? Aghds! I don't know what we're going to do.
As far as behavior when we get home, our birds hear us come in the door and start flock calling, they are soo excited to see us. As soon as we can we put our bags down and get our birds out and all is "normal" again in their world.
We are leaving next week for 4 days on a hike...it's the longest they'll have been left since they adopted us, I'm a bit on edge, but I know with my daughter here, they'll all be just fine.
Have fun on your trip and no worries, I'm sure your bird will be just fine.

(easier said, then done...I know)
Toni