why wont she give me the key
Because her interest level has declined...
My guess is...your spending too much time with her, you show needy behavior, and shes beginning to look for a way out of the relationship. WHY IN THE HE11 you have keys in the first place is beyond me.....stupid. Dont move in with a girl or get keys to her place unless your engaged to her.
Now....as I said, shes looking for a way out. So if you act insecure or p1ssed off over this....thats exactly what shes going to do....dump your a$$. My advice would be to act unphased. Who cares if you dont have keys to her apartment pal?? You have keys to your own apt still correct? And she still lives at her apt so if you want to visit there is this thing called a "door" which she can open.
Act like you dont give a sh1t about the key thing and REFOCUS yourself from your girl ----> Your life goals.