Have you starting taking any new medications lately? Many psychiatric and other meds can affect sex drive.

I also agree with Rhapsody about the depression. Have you seen a doctor about this?

Sexual problems can be soooo frustrating. I have had my own issues where I have wondered what was wrong with me or why I was feeling a certain way. It's a good thing that you feel comfortable talking about it (at least here anyhow). Many people are too embarassed and therefore don't get help for what might be a simple problem.