Sudden loss of appetite

[blinky]

DD was 9 weeks premature, born weighing 1.48kg. She now weighs 5.3kg and is 16wks old.
She was started on a bottle from birth as she was kept in hospital and i fed her expressed breast milk.
Ten days ago the breast milk started to give her terrible griping pains and wind, and it was disrupting her sleep, so we took her off it for 2 days and put her on formula whilst i changed my diet.
Returning to breast milk, she was exactly the same, doubled up in agony, so we went back to formula.
During this time, DD's appetite decreased significantly from 800ml a day to 500ml and we put it down to feeling off colour because of the pain and being over tired.
Now the griping pains have subsided, DD has never recovered her appetite (we're still using formula).
She never shouts for food and last night she went from 11pm-7am without a feed and at 7am she still didn't seem hungry.
She usually drinks the first 50ml quite hungrily and then plays with the teat as if it's a dummy.  Feed can take up to 45 mins.
We've changed teats 4 times, given her warm milk and cool, fed her when she's supposed to be hungry and not hungry.
I don't know what else to do. Any hints please?

[LŠuren]

Can I ask was she taking 800mls EBM or formula?  Formula is made up totally different to breastmilk and she may not need as muck formula compared to EBM. How often do you feed during the day - can you post your routine?

Are you also regarding her a 5week old (adjusted) due to that fact she was premature?

The only advise I can offer about the lack of appetite, especially over 8hours is to check it out with your doctor, if you are in any way worried or your intuition tells you something is wrong then gt it check out.

I have just done a calculation and 800ml = 27oz/600ml = 20oz. The rule of thimb in the UK is 2.5 - 2.7oz per lb baby. Your Lo is 12.6lb (5.3kg) - you also need to bear in mind the fact she is a premature baby.

[woopster]

Blinky, did you change your diet 10 days ago?  Have you tried anything new? Any medication?

[blinky]

Thanks ladies, you must be getting fed up of me now! 

Our routine is

Wake at 7am
bottle of formula
acitivity

Nap 8.15-10.15am

Wake 10.15
Top & Tail
Bottle
Short activity

Nap 11.30-1.30

Wake
Bottle
Acitivity
Nap

5pm bottle
nap

7pm bath
bottle
bed

10.30pm dream feed

4am wakes - sometimes feed, sometimes dummy

She was taking 800mls EBM, we feed every 3-3 1/2 hrs during the day, cluster feed in the evening which she doesn't really respond to at all. Dream feed works better.
I was trying to stop the 4am feed but i feel so bad that she might be hungry as she hasn't had as much during the day.
Today she just had 160ml at one feed (no loss of appetite there) and the next feed 35ml.

I have changed my diet but we haven't given her EBM again so it wont' make any difference.

I was thinking of taking her to the docs today as she's clearly different but then she drank 160ml at lunch time.

I suppose one indication of whether she is getting enough or not is whether her nappies are wet and they are, every time - and really quite wet.

Thanks for your advice
Blinky