From http://members.tripod.com/~S_Larson/latindict/LatinDict_A.html (beware of pop up windows),

angor -oris, m. compression of the throat, suffocation; of the mind, distress, anguish, trouble.

animus -i, m. the spiritual or rational principle of life in man. More specifically: (1) the seat of feeling, the heart; 'animi causa', for pleasure; loc. (or genit.) 'animi', at heart. (2) character, disposition; as a trait of character (esp. in plur.) courage, spirit, vivacity; also pride, arrogance. (3) the seat of the will, intention: 'habeo in animo', I am resolved. (4) the seat of thought, intellect, mind, memory, consciousness.

It seems like the expresion is also a sort of play on words, essentially meaning "distress for your life" as well as "anguish at heart."