Switching formula

I was breastfeeding for 5 weeks and my supply is not meeting my babies demands at all…. Decided to switch to formula, and I’m wondering how to transition? Cold turkey or half & half? We were also told my baby is very colic at monthly and 2 week check up. So which formulas are best should I call ped on Monday & get her recommendations or is it a decision I’m able to make on my own? I looked into purchasing Nutramigen.

HISTORY WITH FORMULA:

While my milk wasn’t in the hospital we started with Similac pro-advance TERRIBLE for her.

Then around 2 weeks of being able to have her strictly on my breast milk i was supplementing in some formula trying enfamil gentlease because of recommendations I was told… also made colic worse for her.