Is the "stuffing" actually stuffing, like from a chair?  Or could it be
wads of her hair?  If it looks like stuffing from a chair, look around
to find out if she's pulling stuffing from somewhere - a chair, stuffed
animal, etc. -  or getting into insulation (very dangerous) and
eliminate this source.

If it looks like it could be wads of hair, start feeding her hairball
remedy cat food and give her hairball medicine (comes in malt flavor
that some cats adore, and tuna flavor).  or give her vasoline.  A whole
gob of it.  My cat used to lick either vasoline or hairball medicine off
my finger, but, most cats aren't interested, so, you have to schmear it
on them, and eventually they'll lick it off.  Try to put it on their
back closer to their tail, or on their haunches, or they'll get it all
over the house before they stop to lick it off.

Your vet should have told you this.

You can also bring some of the vomit into the vet and ask them if it is
hairballs/furballs.

If the cat is still eating normally, and drinking enough water, then
giving her hairball medicine/vasoline should help.  If she isn't eating
normally, has a dry warm nose, looks at you with pitiful eyes, cries, or
if the vomit starts to smell like something other than catfood, bring
her back to the vet.