O tomb, vaulted bride-bed in eternal rock,/Soon I shall be with my own again- Antigone says this, but to whom is she talking?
In Sophocles' Antigone, the title character defies King Creon's order that Polyneices should not be buried and is therefore sentenced to die. Creon orders that she be sealed up in a cave-like structure and left to die.
At the point in the play to which your question refers (this starts at line 891 in the Greek text), Antigone is being led away to die. Creon and the Chorus of Theban Elders are on the stage when she makes these comments, but Antigone does not appear to be addressing them.
Oh my tomb and bridal chamber—
my eternal hollow dwelling place,
where I go to join my people.
(Ian Johnston translation)
Grammatically speaking, Antigone is addressing the place in which she will be entombed. This kind of address is known as an apostrophe, a Greek word that means "turning away." Thus, Antigone turns away from Creon and the Chorus and directs her comments towards the rocky hollow in which she will be imprisoned.