It sounds like she has a case of separation anxiety–not just grieving. I think there are several threads here on handling separation anxiety--which is a pretty difficult situation. I went through the same thing when I had to have Max's lifetime companion put to sleep. I got help from a veterinary behavioral specialist.
I agree. She should be through the grieving process by now (5 months later), and it may have developed into SA. Sad to say, it's generally not easy to fix, but it can be done with a lot of time, patience and love. You might want to Google it and see if the symptoms fit her behavior patterns and how one can start on the road to alleviating it.
Poor baby. Good luck.