Help with new Althera SMA for possible cows milk allergies

I’ve just been prescribed SMA althera for a possible cows milk allergy as he was throwing up nearly every feed and screaming in pain. We’ve so far had two bottles and hes thrown the entire bottles of this back up! Even the normal formula wasnt this bad. Do i need to give it a few days until it settles in his stomach? I’m worried hes not actually having any intake - this is horrible for him 😭 (7 nearly 8 week old)