@crazyydudee,
Have you asked her just what she thinks the similarities between you and her father are? It could be a lot of things - appearance, mannerisms, sense of humour - does it really matter if you are as much in love as you say?
Meantime, Punkey is right, try and get your girlfriend to have some grief counselling. She ought not to be consumed with grief in this way. Of course, she will miss her father, and if he only died last year, it will still be pretty fresh in her mind. Added,of course, to just how he died! Was it an accident, a sudden death, a death at the end of a long illness? Any of them would have been pretty traumatic. But crying so often isn't good for her - she needs to work through her sorrow with someone who is trained to help and advise.