The antecedent to this phrase is in Revelation 16:6, with its reference to God's giving people “blood to drink.” Those words in turn recall the consequences of the outpouring of the wrath contained in the second and third bowls (Revelation 16:3–4). That is what is meant by the phrase your judgments.
7 And I heard the altar saying, “Yes, Lord God the Almighty, true and just are your judgments!”