I don't think you just lose it. I think it comes and goes in phases. Perhaps all that's changed is your perspective, and with a new perspective you need to figure out how to vent it. I believe you'll get it back. Don't try to force it. Wait to write when you are feeling inspired, regardless of how long it may take.
It isn't the type of thing that can be lost. The edge grows dull, that's all. Writing requires long hours of writing. Remember when you were writing a lot? Yup, you were writing a lot. I can say this, because my edge has grown dull several times... it hurts. It might feel like you've lost it, but you haven't. One great way to take it to the sharpening block is to search out interesting blogs and write an honest opinion. I'm in the process of that right now. And don't worry. These feelings are felt by most writers. Just write.