Aww, I am so sorry to hear that Karen, sadly that is part of nature, the only thing you can do is keep a close eye on the others, and if you have some scales, weigh them daily to make sure they are all feeding well and step in if not.
i do think it odd that the vet didnt spay her, as it means another anaesthetic. As for the blood, cats do bleed after birth like humans do, so the spotting could be that. It isn't that unusual for mums to try and move their babies, but it is normally when they are unhappy at the place they are in - do you remember which one it was that she was moving? They can sense if there is something wrong with a kitten, so this morning's events could have something to do with it. not sure about how long before they should be usign the tray, hopefully Teresa or Dawn can help on that, if not, a call to the vet.