I'm not sure if yours is the same, but the Costco Kirkland formula here is made by enfamil and is the same product- it costs more than 50% less when you work it out and all the babies I know that have used it have done great on it. Good for you for giving breastfeeding a shot despite all the challenges, but IMP fed is best
We used Costco Kirkland formula exclusively for our two kids when they were formula feeding. They liked it and it was a great value. It actually mixed up better than Enfamil (less clumps). It is made by the same company but has a slightly different "recipe." It tastes a little bit different, but again, our kids seemed to like it better.