I'm really sorry about the lose of your dad 
I can see how the dog is helping with your grief, and it is something lots of dog owners can relate to.
However, you really have to admit that this is something which is purely for your benefit and not for the dogs.
The dog is massively stressed by this situation - a change in owner and routine - and is over bonding to you. You HAVE to do something about this, because it is cruel to the dog to keep this situation going.
Sleeping with you is not helping. In fact, it is more than likely making things worse.
The dog needs to learn independence, and that she is safe without you. She needs to lower her stress levels when she is around you and 'guarding' you.
Please, for the sake of this dog, you have to work on this, and that includes having the dog sleep somewhere else until she can cope with the stress and separation anxiety. The longer you leave it, the worse it will get and the more stressed and upset the dog is going to be.