Best not be greeting her with "Hi hon, how was your day?" School is all she has in her life right now. You're out of HS and have other interests. So your two worlds are quite different now. I'm betting that when you unload on her, she is at least thinking "who cares about your university?" So what to do...
First recognize that you two are living in two different worlds now. She doesn't care about your university and you don't care about her HS. BTW, spoiler alert, university isn't the real world either.
Second figure out why you two are still a couple. What's the attraction (other than physical)? What do you two like to do together?
Finally, when you figure out what you two like to do together, when she starts to whine about HS change the subject to those things you both enjoy as a couple. Something like, "Uh huh, tough, but did you see the reviews on that new movie that's just come out.....?" Assuming you both like to go to the movies.