5 week old vomiting

I need some help. I have an almost 6 week old and since she was about 2 weeks old she has been legit vomiting.

She was diagnosed with acid reflux and put on Zantac but it didn’t help. Everyone who I tell thinks I’m overreacting with spit up but this is not spit up it is legit vomit.

She gags and then her tongue comes out and her face gets still and I can feel her belly working it up and then she vomits. She literally does stuff we would do sitting over a toilet. I have no idea what to do she’s otherwise fine

I am exclusively breastfeeding

Edit: I have spoken to her dr and he and everyone else thinks it’s spit up not vomit. He prescribed Zantac but she would gag and vomit that up so he said to stop it. I should of put on she normally only does it when she goes to eat right before she latches she will gag and then make herself vomit

I’m wondering if she has a super sensitive gag reflex??

Thank you guys for your feedback!