hi CM, I wouldn't think that she is enjoying the w/end, this doesn't happen when you are depressed and unfortunately a depressed person isn't particularly concerned about the effect it has on the person they loved when in this relationship, this doesn't mean that she doesn't love you, it just makes the situation for both of you to be difficult, at for you who has been cut off.
I agree with Lightbeam, it's a good idea for you to understand what depression is all about, I know that you can definitely feel what it's like to be on the receiving end, however if you can get the booklet from BB by going to 'Get Support' and scroll down to 'information resourses', this is free but it will help you try and understand what she is going through as well as what you are struggling with.
All the things that you both enjoyed won't be happening, especially by her and now for you, but I'm worried about as well as I believe that you should go and see your doctor for a diagnosis, and I say this because it's affecting you to a great amount of anxiety, and this anxiety will only breed to a greater extent, such as not eating nor sleeping.
Can I just say that at the moment she doesn't know or unsure of where she is and won't know why this has suddenly come upon her, and remember it's not your fault why she feels like this, and not to take it personally, because sometimes depression just knocks on our door for no valid reason at all.
You are going to have days which will change so much, one day you could cope, but then the next day you will be a mess, and although you won't feel like doing anything, then try and go for a walk, it's going to be hard, but I know exactly how you feel, just as those who have replied as well. Geoff.