Formal:
* Mwen fatige. (This is the most common and formal way to say it in Haitian Creole)
Informal:
* Mwen bouke. (This is a more casual way to say it, meaning "I'm worn out")
* Mwen tranpe. (This literally means "I'm soaked," and is used to express being physically exhausted)
Other expressions:
* Mwen pa gen fòs. (This literally means "I don't have strength")
* Mwen vle dòmi. (This literally means "I want to sleep")
It's important to note that these are just a few examples, and the specific phrase you use will depend on the context and your relationship with the person you're talking to.