Yes, all of those three are possible meanings of .
* !
It's irritating! / It gets on my nerves!
*
I will definitely be angry if I read his letter.
*
My mother gets irritated whenever she sees the face of my father.
( is also fine; see: Habitual aspect)
"!" is used typically when the speaker is already upset, but if I understand correctly, English speakers don't usually say "I'm being irritated!" when "It's irritating!" is enough, either.