Poor little love, her cat died and she's been crying her heart out all afternoon.
cry (one's) heart out
To cry for an extended period of time. Poor Jane really cried her heart out during the funeral service.I can't watch those sappy movies because I just cry my heart out every time.
cry one's heart out
and sing one's heart out; play one's heart out; sob one's heart out
Fig. to do something with vigor or intensity. She suffered such grief—alone and sobbing her heart out.The bird sang its little heart out each morning.