What do you do when you've lost your passion?

I've been dragging my heels when it comes to my writing of late. Between June and November '09 I wrote 46,000 (first draft) words of my historic novel. The first six months of the year had been spent reading for research and thinking; and as one of my teachers at Tafe always drummed into me "thinking time is writing time", but now my thinking is working against me.

The problem is I think I've lost my passion for the project and, as I discussed with a writer friend today over coffee at my local cafe, I feel guilty about it. I've spent a lot of time developing this novel idea and I've put in a lot of hours at the keyboard. The thought of abandoning it and moving onto something else (or back to something else as the case may well be) just feels wrong.

I'm holding on at the moment; trying to figure out if this is just a block I have to push through as opposed to a real lack of faith in the project and/or my ability to see it through, or perhaps even a normal down period (for want of a better word) after completing a previous project - my short story collection Reflections.

I guess I could try and write my way through it but I feel this disconnection with it at the moment and I'm not convinced I can find that spark of interest again. I can take a break from it; I have some poetry I could work on in the mean time & a few short story ideas that could use my attention.

And of course there's that other novel...

I guess I'm worried that if I do move on to other things and leave it by the wayside that this novel will be there in the background (like some spectural being) nagging at me, calling me a coward and a quitter...