And every player that I've met who made the transition from player to umpire has always said the same thing: it's a whole different game once you put on the uniform. Calls that seem so clear to players present themselves differently to umpires. Players see chests relative to the bases. They see bodies. They see players.
We're watching feet, hands, the ball, gloves. We're listening for the sound of the ball hitting the glove relative to the thump of a foot on the bag. On a possible trap, we're listening for one noise coming from the outfield and not two (the thwack of the ball hitting the glove and not the *thud* *thwack* of a ball bouncing, then being caught). Sure, the throw beat the runner, but the first baseman's foot was slightly off the bag, or the runner extended their leg and hit the base first. Sure, the runner beat the throw on a sliding play at the plate, but their foot was up in the air, never touching home, and the catcher tagged them before their other leg hit the plate. It's almost like we're watching two different games.
I'm not saying that your umpire didn't make bad calls. I've made plenty, and I'm sure everyone else here has blown a call (or 50) over their lifetime. And I'll bet you my next season's paycheck that you'll blow a call, too, and someone will be writing about you on some forum or blog. That's the job.
However, the fact that you ask questions to other umpires about plays ("Is this correct?" "Why is this not INT?" "Why is this not OBS?" Etc.) shows that you'll take the job seriously, which is more than what I can say for some other guys. Keep asking questions. We'll be here.
Good luck to ya!