“The day is coming when I’ll look into that man’s eyes, my Doctor, and he won’t have the faintest idea who I am. And I think it’s going to kill me.”-River Song, The Impossible Astronaut.
This scene breaks my heart for River. Here we see her, trying to get back on track with the Doctor. Trying to see where they are in each other’s timelines. But the thing is this regeneration, Ten has just met her for the first time and doesn’t seem to know who she is. He has no idea how important she is and will become in his future. And you can see in River’s expression her heart break when he asks who she is. River a strong independent woman who was born to kill his future self ends up falling in love and ruining time to save him. River a daughter born of Amy Pond and Rory Williams two wonderful and brave people. River a woman who will do anything to protect the Doctor and to make sure he still has a future. And she did all this for Ten despite him not knowing who she was. She sacrificed herself for love and for him so he could still go on to become the man she falls in love with, and the man he will become afterwards. So yes, this breaks my heart during this scene for River.