I think you are depressed because you feel out of control and lost. I have felt that way, and I know I have made others feel this way. I am so sorry. It also sounds like you made her your world because she's the best thing that's ever happened to you. Give it a few more days to get your thoughts straight and prepare for any possible outcome. Take her to a restaurant where you can talk and say the following:

I love you and you mean the world to me. Obviously there are some things I am doing that is irritating you or something I am not doing that you would like me to. Tell me specifically what you want me to not do or what you need from me. I am willing to work this out because you mean that much to me.