Suddenly sick on formula

[Sc4nDal5]

I'm combination feeding my 3 week old and have done since birth as was premature and my milk wasn't established. He's suddenly started throwing up all formula feeds (same formula - pre-made so no variance in that) and not feeding the same volume. My milk isn't producing enough to EBF so need him to feed on both - any advice?

Have you asked your doctor about your low supply? (Sorry if that's a stupid question!) They might be able to find a cause, or suggest ways to increase it. I've heard that lactation cookies can help.

Are you happy to combo feed? What would your ideal scenario be?

*combi

Combi feeding as I'm not producing enough milk to EBF. He also lost 400g when born as wasn't taking on enough due to tongue tie (which we sorted) but am hyper sensitive over it! Ideally want to combo feed also so his Dad can help out with night feeds!

I've been advised I need to BF at night as apparently that puts the order in for the following day but I'm not then making enough during the day to supplement him.