Very liberating. Also, one's notice period (assuming it's not too long) is always a reasonably fun time, since one is to some extent freed from the requirement to pretend to like certain people or care what they think.
Once you have made up your mind to seek alternative employment, you have effectively left your current place and should feel the same imo. Unless you are some kind of insecure jellyfish.
And when you've handed your notice in you stop 'working' as such and become merely a handover conduit.
Congrats, b, btw
“Other clubs never came into my thoughts once I knew Arsenal wanted to sign me.”