Formal:
* من گیج شده ام (Man gij shode am): This is a very formal and direct translation of "I'm confused".
* من سردرگم هستم (Man sardargam hastam): This means "I'm bewildered" or "I'm lost" and is a more formal way to express confusion.
Informal:
* من قاطی کردم (Man ghati kardan): This means "I'm mixed up" or "I'm all messed up" and is a more informal way to say "I'm confused".
* من سر در نمیارم (Man sar dar nemiarem): This means "I can't understand" or "I don't get it" and is a good way to express confusion about something specific.
More idiomatic:
* مغزم سوت میکشه (Maghz-e-man soot mikeshe): This means "My brain is whistling" and is a more figurative way to say "I'm confused".
* نمیدونم چی به چیه (Nemidoonam chi be chiye): This means "I don't know what's what" and is a good way to express general confusion.
The best way to say "I'm confused" in Farsi will depend on the situation and your relationship with the person you're speaking to.