Projectile Vomitting?

i feel I've been asking a ton of questions lately, so I apologize to anyone stuck reading my constant posts. FTM after four years of struggles so I'm a worrier now with my girls.

My twins are 6.5 weeks old now (but we're 6.5 weeks early, today was their actual due date) and as of last Monday were gaining weight appropriately. The lactation consultant comes back this week and they will be weighed again. We are working on Breastfeeding but both babies had a hard time latching so it's a work in progress. I pump and feed them 75% breastmilk and supplement the rest with formula as I can't seem to pump enough for both of them.

Both girls have been notorious with spitting up after eating as they almost always get the hiccups. This has never been a large amount. However in the last week or so the one twin has twice now projectile vomited up everything she just ate to the point she was choking and it was coming out of her nose too, with no hiccups to blame. She's now spitting up randomly 30-40 mins after a feed and if we are burping her there's an excellent chance that if she burps she's also going to regurge.

So my question is, does this sound more like reflux or something else entirely? Notnsure if all babies do this and I'm just over reacting. But her sister has never done it so I'm starting to worry something else is going on.

Thanks ladies!