Is your B complex a complete one, all the B's? I would keep at it, sometimes they can show improvement really quick, sometimes it takes longer. The B's are very safe, no worries of too much, extra will be excreted in droppings. You might consider adding a vitamin E capsule (400 iu) as well, give that for a week or two, see if it may help also. The E's can be overdosed, so that one can't be given as long as the B's. The sling is a good idea, it will help her stay upright, make it easier for her to eat and drink and poop normally.