I think a pathetic fallacy is more specific, in that it refers to human feelings attributed to physical objects. Personification can refer to a wider spectrum of human qualities. "The alarm clock screamed into my ear" is personification but indicates no particular feeling.
pathetic fallacy is where the mood is represented by the weather e.g if it is sunny out, everyone seems happy whereas if there is a storm it's very likely that someone will be killed at some point in the next scene.
personification is where you give an inanimate object traits which would normally be associated with people.
e.g the tree was sad (sorry couldn't think of a better example)
This entry for "Pathetic fallacy" from A Handbook to Literature by Thrall, Hibbard, and Holmna may help:
"A phrase coined by Ruskin to denote that tendency of poets and writers of impassioned prose to credit nature with the emotions of human beings. In a larger sende the pathetic fallacy is any false emotionalism in writing resulting in a too impassioned description of nature. It is the carrying over to inanimate objects of the moods and passions of a human being...."
While personification can involve the attribution of emotion to inanimate objects, it usually involves other abilities or qualities and does not have the over-the-top emotionalism found in writing to which the patheticfallacy can be applied.