Rashi: Your breakage is grave.

Radak: I explained above Anush (pain and breakage - 17:9) and Nachlah (a severe wound - 10:14). The Lamed in l'Shivrech is superfluous. The same applies to "l'Amos Chamesh" (Divrei ha'Yamim II, 3:11), "Hargu l'Avner" (Shmuel II, 3:30) and similar verses. It is in the feminine, corresponding to Keneses Yisrael. Even though now your breakage is grave, you will have hope, and all who harmed you will be punished due to you - "Kol Ochlayich Ye'achelu" (verse 16).

Malbim: Your external breakage is very dangerous, and also your inner wound is very ill. When they come together, they are difficult to heal. This is a metaphor - your physical illness is your affliction, and your spiritual illness is your sin.