I've had the same problem since August of 2010. Hadn't sewn a stitch since early that month. Yikes! I was in two different round/row robin projects AND a boomerang swap through this board, and just could not bring myself to do it.
I knew what the problem was: things in my personal life were just too overwhelming for me to create. And although I didn't stress too much about it (I couldn't ... it just made the problem worse), I still was concerned, especially since so many people were counting on me to come through for them. Eventually, it did come back and now I am back at it (finally!).
But here are a few things that might help: walk in to your sewing space and work ... not on sewing, but sometimes it helps to re-organize your space. That way, you come across some things you may have forgotten you had, and sometimes touching a certain piece of fabric or a left-behind and somewhat forgotton UFO will do it. But cleaning up the space you use to create can motivate and even jump-start your creativity.
Sometimes I just spend time online doing a little "window shopping" for patterns (usually free), or fabrics (inspiration -- and free unless I decide to buy something!), or projects (some are low-cost). It doesn't have to be expensive, just something that might jump-start the creativity.
But the best thing is to not sweat it. Your muse will return, and when it does, you'll create like there is no tomorrow! Best of luck to you.