Μούνη γὰρ ἄγειν οὐκέτι σωκῶ λύπης ἀντίρροπον ἄχθος → I have no longer strength to bear alone the burden of grief that weighs me down
firmly, fast: V. ἐμπέδως, ἀραρότως (also Plato but rare P.).
eternally: P. εἰς ἀΐδιον.