“Man, I am so exhausted!”
You stayed up late last night and only got a few hours of sleep. You are riding the elevator at the end of the day with a coworker who you are good friends with. You say this, complaining to him about how tired you are.
Man, I am so exhausted!
The expression "Man!" shows strong emotions, like shock, fear, admiration, envy, surprise, annoyance, etc..
Man, I am so exhausted.
Man! This computer is taking forever to start up!
Man! What a gorgeous sunset!
You can use "Man!" when speaking to both men and women, because you're not saying it to anyone. You just say it to show an emotion.
"Man" is casual, but it's completely polite. It's a lot more polite than other words with similar meaning, like "Shit!"
"Exhausted" means "very tired".
When you want to emphasize the word "exhausted", you can use adverbs like these:
I'm so exhausted.
I'm completely exhausted.
However, it doesn't sound right to say "I'm very exhausted". That's because "very" is already included in the meaning of the word: "exhausted" means "very tired". Adjectives like this are sometimes called "ungradable" or "extreme" adjectives. Here are some more examples: