Vomiting while switching from breastmilk to formula

my lo was jaundiced but doctors wasn’t sure what the cause of it was, they suspected it was breastmilk jaundice n asked us to try feeding formula for 1-2feeds per day for a week n then we’ll know. so we did, we fed her formula at 7weeks old n she vomited immediately afterward, like really vomit, even came out of her nose. we brought her back to doctor the next day n they told us that it’s not really a big deal if vomit comes out of baby nose when they vomit (not spit up), u can google about this as i don’t remember what they said. anyway, she didn’t like formula at all. so i only fed another 3-4times n stopped but she vomitted 3times