J.K.
Lots of good advice here, especially reflux and maybe GERD could be looked into as well. Perhaps some trouble with her esophagus or upper stomach? Ulcers? Could also be teeth coming in (gums bulging or red?), but keep her comfortable, with very light exercise. For doctor, keep notes of what/when she's vomitting and what she isn't. Maybe flavor or food (allergy?) or consistency?
Keep her on the crackers/rice/bananas/applesauce like with other vomiting, and don't feed until 1 hr after vomit of anything, including fluids. Then, little every 15 min with 15 min between to watch. Continue to give her formula, lots of nutrition there and if she can stomach a multivitamin, that might help as well.
Lots of luck and let us know how it goes:)