4 week old feeding

[Kieryysmithyy]

My little one is now 4 weeks old.
And feeding is a nightmare.
He doesn't wake up for feeds when he should and trying to get the "recommended" amount into him is a struggle.
Some feeds he will take 110 (takes abit) and other feeds he takes 40mls. Usually every 3-4 hours. Sometimes he sleeps for up to 5 hours at night. I try to get more than 40mls into him and he threw up a bit. But then when he takes 110 he doesn't throw up? He burps well.
Anyone else's LO like this? How can he go from 110mls for 3 consecutive feeds in a row to the next 2 feeds after that being only 40 - 60mls? With the same time gap in-between.
Any advice?

Sorry, should have specified this, he is formula fed.

Hey, midwife here! He may want varying amounts with each feed as milk for babies provides not just food but also a drink, it's their complete source of hydration and nutrition. One feed may be satisfying his hunger, the next his thirst if you see what I mean?

Each baby is different, and if he doesn't want to take more than the recommended amount at some feeds then that's fine. Try winding him, giving him a quick break and try again. If he's still had enough then listen to his cues and look out for his hunger cues again over the next couple of hours and try again if he appears like he wants to try and feed again.

If he's having good wet and dirty nappies, settles after a feed, doesn't appear to be unwell in your opinion, you don't have any other concerns, and your midwife/HV haven't been concerned about his weight then I would be inclined to say that all is well.

I'm having to wake him every 3 hours for a feed, trying to get 90ml into him each feed, was told to do this by a nurse as if I just leave him and follow his cues he doesn't have enough or doesn't wake up for feeds, or he wakes up and only has 20ml. But then I'm being told by another nurse to follow his cues, don't wake him and feed on demand. So very confused.

You can ask 10 different healthcare professionals and get 10 slightly different opinions on feeding - there's no one size fits all approach.
The advice I decided to follow was to follow feeding cues, that once they're over birthweight you can generally stop waking them (my 7 week old feeds much better if I let him wake up naturally) and that if the amount they take averages out over the day then it doesn't matter if some feeds are bigger/smaller (I.e. if he's meant to take 50ml every 3 hours, then as long as he takes around 400ml in the day then that's ok).
Every baby will be slightly different so I'd treat the volumes as a guide - as @USaYwHatNow said, if they're having good nappies, gaining weight well and otherwise happy you're doing it right

I've got 4 and 3 are babies...Guess what mum you can listen to all the medical advice in the world but only you know your baby...dont wake and annoy baby he isnt hungry he is tired.Trust me you will know when he is hungry...one of my girls and the boy they slept all night then wake around 7am guzzle guzzle milk all day happy as anything then sleep all night....our other girl she wakes once in the night for a bottle...I stopped listening to all around me and went from 3 unhappy babies being woken up and not hungry to now 3 happy babies all healthy and chubby

Sorry I should of added. He was in hospital a week ago due to gastro. He is having gel 4 times a day because of thrush and he is also very colicky. Think I'll just let him sleep and I guess when he wakes up hungry ill feed him then. So hard to know what to do at times like this. Doesn't help that I have my 2 year old being a turd.