If you dropped 8 freaking inches off your waist while increasing arms a full inch and a half, you have a dramatically different physique, and I'm betting most of your clothes are fitting differently. That should be a daily clue.
A progress picture (to compare with your avatar, for example) would be a simple way for you to have a "Holy shit, it really did work"-moment.
It's normal, like the guys have said. But it's not the best thing for motivation, and it's why some guys do end up with legit "bigorexia", when they're a lean 220 pounds but keep talking about how tiny they think they look.
It's also exactly why you do want to track progress via several methods (feedback from people and measurements and progress pics, for example).