It is worth bearing in mind the following though before you start to worry so you don't become disheartened:
On top of all of this, the amount you can pump varies from mom to mom — and it has nothing to do with breast size or milk supply! It may be as little as 0.2oz or as much as 7 oz.
Plus, don’t worry if your little guzzler seems to be taking more milk from the bottle than you are producing in one pumping session. This does NOT mean that your supply is low — the fast and steady flow of baby bottles just means they feed faster and may not realise their little tummies are full.
Finally, remember your milk production will vary depending on how you are feeling. Tiredness, stress, even hunger can all take their toll, so try to put your needs first and take care of yourself. It's not being selfish – a happy mummy really does equal a happy baby.
For more information about the amount of milk you should be pumping, contact your doctor or a similar suitably qualified health professional.
Can I heat breast milk that has been pumped?
How often should I pump?