Formula Feeding / uncertain CMPA formula

[LifesABeachx]

Does anyone have any advice or been in a similar situation

LO is 3 weeks old. We used kendamil ready made for the 1st week and then gradually switched to standard kendamil, when he was 12 days old, fully switched.

He was great on ready made, all be it was a new baby. However once the switch was made he displayed tummy struggles, excessive grunting at night and struggled to pass wind.
We started to give him infacol.
He then broke out in a facial rash (not sure if this is linked) and his nappies were runny like water. However, he never cried and even he was unsettled, was still pretty chilled.

I took him to the GP who has prescribed non cows milk formula for CMPA. They've asked us to trial it for 4 weeks, then if things get better return to the formula we were using to be sure.
Within 24 hours of using the prescribed formula, I have a different baby and not in a good way. He won't finish his bottles, he's passing wind both ways but is screaming non stop. This is completely out of character for him. He's also bringing up reflux and choking on it.

I don't know whether to continue with the prescribed formula or to switch him back until I can attend the GP again.
Wishing we tried a different formula brand first before going to the GP hut panicked as his stools were so loose.

One stressed mum right now 🙁 worried about doing what's right!

24 hours is enough to get a response to a change, with no opportunity for it to settle into something positive or negative.

I’d give it 4 days and see whether this change remains, or whether things settle.

Also, check you’re making it as per the instructions.

If he was fine on the ready made formula I’d switch back to that. Infacol didn’t suit my dc. They also had issues initially with wind, squirming and appearing uncomfortable, it was just their digestive system starting to work and them needing to learn how to pass wind / poo .

@ScaryM0nster I've saw online that you can ease them into it by mixing their normal formula with it 1 scoop at a time.
the GP didn't advise that and we've just made a total switch, unsure if it's too much.

So much uncertainty. But you're right at least another couple of days should determine how he'll be with it. Just struggling watching him go from a pretty content baby to screaming and purple!