It's most likely you're thinking of one of these:
* Out of my mind: This means someone is acting irrationally or incredibly confused.
* Out of my reach: This means something is inaccessible or unattainable.
* Out of my league: This means someone is considered to be too good or impressive for you.
* Out of my way: This means to go to extra effort to help someone or to deviate from your usual course of action.
* Out of my depth: This means someone is in a situation that is too difficult or challenging for them.
Please provide the full phrase you are interested in, and I can give you a more specific definition.