Enfamil AR

Started the Enfamil AR and LO was eating great but tonight she scared me!!! She choked on it because it is so thick. She almost turned blue. I ended up giving her a few sips of water to clear her mouth out. She eats so much more on the Enfamil AR where as when she was on the gentlease she would barely do 2 oz or 2 1/2 oz. Has this choking on the thickness happened to anyone else? She’s 1 month and 4 days. Her spitting up has stopped completely but I don’t know if it’s helped the acid reflux completely. But the choking scares me.