Hi Mama of 2, you must be pretty busy with your 3mo and another child as well. If fatigue caused loss of milk, I don't think any of us would manage to breastfeed successfully! Yes, it's actually quite common for mums to feel as though they might not have enough milk, and around the 3 months mark is a very usual time for it to happen. A lot of babies have a "fussy" period around then, also many learn to suck more strongly/efficiently so they will drink the same amount in less time. Plus your breasts will have adjusted to making milk, so they won't tend to feel as full as in the early days.

The first thing I'd suggest is don't look at your breasts, look at your baby. Check the signs that she's getting enough to drink (she's growing, gaining some weight, looks healthy with nice tone, bright eyes and wet mouth, she is producing plenty of wet nappies, she's fairly contented for a good portion of the day etc). If you are at all concerned about her health, get her checked by your doctor or child health nurse.

Things you can do if your supply is a bit low: breastfeed more often and don't limit her sucking time (easier said than done when you have another child, I know, but remember supply matches demand so the more she sucks the more you make). If she uses a dummy, you could try letting her comfort suck at the breast instead. If she seems hungry and unsettled after a feed, you can offer her a top up feed about 20 minutes later. If you seem to have more milk in the morning and then run low in the evening, you may like to express some in the mornings and use it to top her up later in the day.

You could also phone the Australian Breastfeeding Association helpline - the counsellor will be able to go through your situation in detail with you, or if you'd rather, they can send you info in the mail.

BTW, you don't need to drink ridiculous amounts to keep up your milk supply, just drink as much as you feel comfortable with.