Hi, forgive me if you've already stated elsewhere that you have done this, but if you haven't read the sticky message in this forum, with links to discussions on labor and delivery, kitten care etc., you would find it helpful I think. Here is the link to that thread: http://www.thecatsite.com/forums/showthread.php?t=74659
Generally speaking, seeing a bloody show like that means the cat will deliver within 36 hours. The panting may mean she's contracting, and it will be important for you to figure out if she's straining/pushing at all with no results. Is she settled in one room, does she have a birthing box or area with towels or what have you set up? Will she stay still and let you sit with her? I'd look to see if she's doing any kind of lying on her side, arching her back and pushing (whiskers will flick forward as well when pushing, at least mine always did this), or is she squatting in her litter box trying to push as if constipated?
Do you have a vet who has seen her during this pregnancy, that you can call for guidance if you are unsure if she's in distress?
Please do go read the thread, be sure she has a safe,quiet, clean area to deliver, be sure you know the signs of labor distress and are clear on when to call the vet...and keep us posted!