A. Unless someone else at home is sick with a stomach virus, that isn't a likely cause of this problem...
Does she do this at each feeding, or only occasionally? If it is not with every or most feedings, then you may just be misinterpreting her hunger signs and are trying to feed her either too early, so that she isn't hungry, or too late, so that she is overly fussy because she is very hungry. Keeping a diary of her feedings for a few days might make it easier to get a good picture of how much she is eating each day and how often.
Some simple problems that might cause this problem is that the formula is either coming out too fast or too slow from the bottle's nipple. When you turn a full bottle of formula over, how quickly does the formula come out? You should get about a drop a second at first. If it is slower or you see a much faster stream, then you might try a different nipple.
You might also consider that her formula could be too cold or too hot. Are you warming her bottles of formula? If so, how are you doing it?
If she is fussy, doesn't want to eat, and spits up a lot, then she could have reflux.
A formula intolerance might also cause a baby to be fussy during feedings, although these children also usually have other symptoms, like diarrhea or a lot of gas. If this is the problem and she is on a cow's milk based formula, like Enfamil Lipil, Similac Advance, or Nestle Good Start Supreme, then a change to a soy or elemental formula might be helpful. Be sure to talk to your Pediatrician before changing your baby's formula though.
At this point, you likely need a recheck with your Pediatrician, especially to make sure that she is gaining weight well. He or she will likely be a little more aggressive now in looking for a cause of her problem now that it has been lingering for over a week. If you are not comfortable seeing the same doctor again, then a recheck with another Pediatrician might be a good idea.