How do i make up with this girl?

We used to be really good friends. Then I accidently took some stuff out on her, and now she hates me, and says im making her life a misery. Ive apologised on her fb page and tried to chat to her and she wont reply. I feel so awful and ashamed and i have to go to her birthday party on the 14th July and i want to make up by then. If you think she is over reacting u r rong i was an ***. Help me...