Wow, I had to wait a couple of hours (I went to the gym) so that I could be coherent enough to comment. Your story is unbelievably good. I LOVED IT! I'm still not lucid enough to state this well, but from the moment I started reading, I knew I was in for a treat. I was holding my breath the whole first scene and I could just sense Severus' desperation and wavering strength. I didn't think the rest of the story could possibly hold up to that because the beginning was just so strong, but it did. It totally did.
Your Harry is struggling so much to put his life back together and his connection with Snape is powerful writing. And your Snape, seen through Harry's eyes, is layered with so many emotions leaking out from behind his anger. I hope I don't spoil anyone with too much info in the comments, so I'll just say that there are scenes that will stick me with me: the role of the stone, Harry's conversation with Snape about "knowing", Snape teaching him one more time, and that lovely conversation at the end, where they're both afraid, yet brave enough to go on together.
You had me in tears with a lump in my throat through parts of your story, and in others with an anticipatory grin. Thank you for a wonderful reading experience! I'll be reading this one again and again (I'm adding it to my Kindle). Now I must look for more of your writing! (And please write more Harry/Snape!!!) :)