Breny,
Im so sorry the last few days have been so discouraging!
Yes Joker was the same, three times smaller then his brothers. As he got stronger he fought force feedings, thats why I went to the cup of formula. It took a brief time but he responded to lapping on his own. I force fed him until then, but as mentioned earlier he would take the syringe of formula in the first few minutes willingly.
I know you are completely frustrated but dont give up. If she isnt getting enough nourishment I would definitely think your weight would be plummeting and her energy level at a real slow.
Still no interest in canned food? Have you tried mighty dog or lil cesars? These arent the best canned foods i the world but they sure are good for getting puppies to eat for first times.
Are you still consistently offering formula in a cup?
Let me know how she is today.