Formula switch

My son is 8 weeks old and our pediatrician told us it was okay to switch formulas. He was on enfamil gentle lease and we switched him to earths best organic. Basically I had to stop breastfeeding and we were supplementing with the enfamil but now that he is only on formula we wanted to switch to one we felt was the most beneficial.

Basically my pediatrician said everything would be fine if we switched and that he will just be a little fussy. Well holy hell this kid screamed his head off for hours. This is his second day on it. Was I not supposed to switch him cold turkey? I feel like a horrible mom for not thinking of that...but the pediatrician also didn’t mention we shouldn’t. Am I okay to give it another day or two for him to adjust? Has anyone ever switched cold turkey and had it end up being okay? Any advice or reassurance would be much appreciated ❤️