I'd say most of us have a harder time with people we dont know or speaking to people of authority. For a lot of pws (persons who stutter), we worry about making a good impression or are afraid of listener reactions. so the stakes are raised when talking to someone we don't know or persons of authority. Basically, you are more worried about stuttering around them, which means you don't want to stutter that much more, and in turn that makes your stuttering more severe. If you want to know how to overcome it, in my opinion you do it by slowly and gradually overcoming it. You don't have to look away or focus so hard on trying to push through a block asap (I know, easier said than done) or change your words because you want to stutter less. Ask yourself, is your goal to not stutter or to say what you want say? If not stuttering is your primary goal, then I think that's going to add a lot of stress since we are people who stutter. But stuttering doesn't mean we cant talk or say all the things we want to. It just takes us longer. It sounds like you're putting a lot of weight on fluency and since we can't always be totally fluent, I think that's going to wear heavy on you.