OCD or obsessive compulsive disorder, can be of great concern to you, as her partner, as you may worry, that her being upset, will throw her off course, and she may have difficulties. You don't not mention if she lives at home with her parents, or on her own, or with friends.
Is there someone else you could contact, and calmly tell them without alarming them, that you are concerned that she has not called, and that you can't get hold of her. They may be able to set your mind at rest, or may know where she is. It is possible that perhaps, she is just taking her time to absorb the shock of a death of a family member, and will need some help. You need to keep doing what you are, and offering support.
Is there someone else you could contact, and calmly tell them without alarming them, that you are concerned that she has not called, and that you can't get hold of her. They may be able to set your mind at rest, or may know where she is. It is possible that perhaps, she is just taking her time to absorb the shock of a death of a family member, and will need some help. You need to keep doing what you are, and offering support.