Thread: Estaba equivocado

"I was mistaken" and "I was wrong" mean the same.

In accordance with what nablym says about "I got confused", you could say "I misunderstood".

You could also say "I made (committed) an error" or "I was in error"

Depending on the type of mistake there are varying ways of saying it colloquillaly or metaphorically ("I screwed up"; "I dropped the ball", etc.)