This story is so painful to read, and I rarely feel that way even in extremely angsty stories.  It's the juxtaposition of a strongly IC Snape, and this very fragile and fearful Harry.  As to Harry being OOC -- well, putting him in Slytherin automatically tells the reader that he's not strong enough and confident enough to object to the Sorting Hat.  What would it take for canon Harry to be like your Harry?  Probably not a lot.  Probably just a bit more abuse from the Dursleys -- not necessarily major physical abuse, just some.  Dumbledore in canon is right to be amazed at how Harry turned out.  Living in a home where the child is put in a closet for weeks at a time (Harry recalls at least one incidence of this in canon where he goes in while school is in session and doesn't get out until after summer holidays had started), combined with lack of decent nutrition, serious verbal and other emotional abuse, and general neglect, is more likely to produce a child closer to your Harry than to canon Harry. 

So, basically what I'm saying is that your Harry may be OOC, but he still makes sense.