Very normal, not a sign of aggression in the slightest. It's a normal developmental stage. How long it lasts varies but the best course of action is to toughen up
Seriously, just keep doing what you're doing. Don't lose your temper, that's not going to help at all and will make you feel worse. Your pup will outgrow this and then ironically enough, you're going to miss it someday. I promise