Vomiting, possible acid reflux?

Friday my 7month old projectile vomited twice. Friday night through Saturday she started refusing bottles and nursing, and we had to restrict her to small amounts of milk supplemented with coconut water (with a little sea salt) to prevent dehydration. Sunday into Monday she started sleeping better again, and was feeding normally.

Today (Tuesday) she threw up again twice. She started arching her back, and also she is holding her bottom lip under her top lip inward (she never did this before) she is also fussier than normal, little distressful coos here and there, not her normal happy sounds. When she is laid down today it sounds like she is about to choke (this is info from her Nanny aka Great Grandma!)

Also sometimes she makes weird faces, like shes burping up some stomach acid.

Is Natrum Phos 6x the right remedy to use?

Other info: She had Flu Type A 2 weeks ago, and recovered in 5 days. During that week she was given Tamiflu, Tylenol and Motrin (we spent 6 hours in the ER just to make sure her breathing returned to normal). She has fully recovered from the flu, but that was the first time she had ever taken drugs.

I give her Hylands Calming, Hylands Teething, and Hylands night time teething tablets and Hylands teething gel on a regular basis, as well as a Hylands Sulphur 30X tab once a day for her Eczema (sometimes I forget to give the Sulphur)