This isn't just a spoke in my menstrual cycle.

I'm quite distressed lately. BFF and I have been having some problems. Nothing outwardly stated, but...I feel like something is off, and I'm rather concerned. Granted, she's had a difficult few months, and Lord knows I've had a difficult 2007 overall, but does that mean that a friendship will suffer when both people are having a rough patch? I know that I should address the problem with her, but it's just a conversation that I am dreading having. I suppose that some of the reason for that is because I know what she will say, and perhaps I just don't want to hear it? I know that she thinks I have not been there for her as much as she wanted me to; but I feel that I have been there for her as much as I could have been. Who is to blame, then? Is anyone?? And how to repair the relationship? There are questions that have been plaguing me the past few weeks, and I'm just not sure how mend things. Any suggestions??