So confused on formula feeding

So I have a 1 week old I tried breastfeeding but that didn’t last as my body couldn’t keep up then just dried up even tho I was pumping.

We started my son on infant Enfamil but he was having crazy spit ups and even tho we are using lvl 0 nipples he keeps choking. A friend of ours recommended we use Enfamil A.R. so we gave it a shot last night. He normally will eat 1 oz then follow up an hr later with .50-.75 oz with the A.R. his 1st feeding he wasn’t satisfied till he had 4 oz and about an hr later wanted 2 oz more.

Threw his feedings last night I would give him 2 oz of the A.R. burp him an then when he started acting hungry again give him the normal formula cus it seamed to actually sooth him he would have an oz and then be good for about 2 hrs.

I was wondering if any one had any experience with this?