Does she actually make the retching motion?
Are you holding her by the stomach?
Does she do the same it you pick her up holding her chest in 1 hand & the back legs & bum in the other?
Does it happen everytime you lift her or only just after she's eaten?
You say hair is more yellow, what about around the eyes?
Perhaps if you can get this on video, take it & her to the vet to show them. I'm concerned about the yellowing usually means there is something wrong w/the liver function.
& let us know what the vet says