I have to completely disagree with the last post. relationships are a 2 way street. Its a give and take situation. First off you need to face her with the question of what type of relationship she wants to have with you. 

Ask her this:

Do you love me? She will undoutedly say Yes.

The problem here is that you can love some one as a friend, brother, sister, or whatever.

Are you in love with me?  This is by itself different in the sense of does she go mush when she thinks about you which is the entrance to a desire for physical touching. If she doesnt quite understand then ask her "Do you think about me?, How does it make you feel?" If its anything but mushy gooey, then Id run.

Pat

if I may throw in my female perspective, my husband has always suffered with depression, it is mostly managed but I can always tell when he's fighting to 'stay above water' and the worst thing I can do is suggest sex! It has always been difficult when I want to be intimate but can clearly tell that would be another exhausting task for him, I have gotten my feelings hurt more than once so we've made a sort of code when we are feeling frisky which is nonverbal but is also not so blatent that it would hurt or embarrass the other. One of the first things I noticed about depression is the lack of sex drive, as is one of the largest side effects in most depression meds. The best thing I can do when he feels like this is a cuddle session, sometimes it leads to more, sometimes I learn that we really don't snuggle enough. Good luck and hang in there with her!