different meanings. If you say "I f*cked up",  that means I messed up, its like an apology,  

it's acknowledging you did something wrong.  "I f*cked up" or "I f*cked that up" or  

"I completely f*cked it up." But if you say, "I'm f*cked up"  

and instead of I you say I'm, then you're saying  I'm really drunk or I'm really high on drugs. 

I'm so f*cked up. Two very similar  

phrases but very different meanings. Quick add-in, if you don't want to cuss,  

you can say "F'D up". "I really F'D up, I'm so  sorry." or "Woow! Last night I was really F'D up."