Really, really, really blows.

Naps have been okay--a little more crying than normal, but bedtimes the past few nights has been horrible. Ear-piercing screams, even when he's being held and rocked. Tonight he was still sobbing while nursing, which just about broke my heart. We're trying to reassure him we're still here by going in frequently when he cries (our "let him for for 15 minutes" is currently shelved). I don't know what else to do.

Have you had this problem? How did you deal with it? Did it eventually pass?