M.R.
My youngest did the same thing plus he was on soy formula for at least 9 months of his 1st year due to acid reflux. I ended up doing 1/2 formula and 1/2 milk, then add more milk and less formula the next day and until he was drinking all milk and no formula within the week plus I warmed it up as well which helped. I ended up having to switch him back to soy and even lactose free milk a few times because he would start throwing up again, also danactive helped as well.
Good Luck and I hope this helps.
M.