I have so many favorites, but the one that sticks out the most to me is "When I'm Alone" by Nevertheless. I ran across a video with this song on Youtube during a low point in my life, and it really spoke to me.
This part especially:
I'm just trying to find out
Who I am on my own
I had you right beside me
But now you're gone and I know
That when the room clears I'm still here
Who am I when I'm alone?
It was almost exactly what I was going through. I won't give exact details, but my family seemed to go their own ways after my parent's divorce and since I was so used to sticking together, it was like I didn't know who I was or what to do. This song really got to me during that time, and for some reason it helped a little, too.