In poetic fashion, the Lord rebukes Israel's lack of faith and understanding by returning the accusation of sleep upon them. Where Israel accused the Lord of sleeping in verse 9, the Lord now indicates that it is Israel who is asleep, and needs to awaken.
The second idea of the verse sets up the next several verses. The Lord recognizes that Israel is in some difficulty (he has recognized them already as captives, though not under more dire or immediate threat) and he notes that this condition is one that they brought upon themselves by angering the Lord. The Lord has allowed their current state. Their misery is equated with the "cup of his fury."
Literary note: The doubling of "awake" is an obvious literary parallel to verse 9, with both doubled sets functioning to set off the phrase and make it memorable to the later (and then earlier) referent.