4wo DD not gaining weight

[Lokidottir]

My 4wo DD was 4.6kg at birth and dropped to 4.2kg by day 5. Due to various reasons, she is now exclusively formula fed. She was gaining weight, albeit slowly, but she's now plateaued at 4.5kg for the last two weeks.
The Health Visitor says we need to feed her more, but we're already doing 2 hourly feeds during the day. We let her drink as much as she wants, and it's generally between 45 - 60ml (1.5 - 2oz). She occasionally will finish 90ml (3oz) and over the course of the day, she'll have around 530ml. At night, we let her sleep but she'll normally wake 3 times for a feed between 9pm and 6am.
The Health Visitor says we should be aiming for 700ml a day, but how do we do this when trying to feed her more results in her projectile vomiting everything we've just given her? The one day this week I got 600ml into her, she vomited 5 times, so she probably ended up drinking less than normal in actuality.
I'm hoping that one day she'll just wake up and be hungrier and start drinking more. Is this realistic? Will she just decide when she's ready to eat more and put the weight on, or is this wishful thinking?
Feeding her is starting to feel like a really unenjoyable military operation and is causing a lot of anxiety.

Not sure I can offer much help but just to let you know you’re not alone.
I’m in a very similar situation and we’ve finally seen an infant feeding team at the hospital and been put on special formula for cow’s milk allergy.
my little boy is 11 weeks old but we always struggled to get him to drink more than they say.
I will say 1.5-2 ounces sounds right for your babies age as does the frequency. At 4 weeks we were told by the hospital no more than 2 ounces per feed (this was to help with his reflux).
also I figured it was physically impossible to fit in more milk than they can! Even after I had a GP tell me at 10 days old his weight meant he should be drinking 4ounces a go! Upon which I put down the phone and burst into tears over the worry and stress of it all.
Apart from when you try to feed her more and she brings it back up, does she show any other symptoms? Crying? Back arching? Anything like that?
Otherwise I’d say you’re doing everything you can. You’re feeding your baby when she wants and she’s taking as much as she can.
I completely understand the anxiety over it. Feeding times for me are my biggest dread and I try to get my fiancé or mum (when she visits) to do it as much as possible because I can’t watch him get so upset.
just remember this is a phase and will pass and you will get through it one way or another.