Have you tried letting her have a little lick or suckle at the Breast during a cuddle.
From 32 weeks both my 28 and 25 weekers latched on...only for a very short time but they did suckle?
Speak to your nurse about if you can have a cuddle around feed time, if possible arrange for the LC to be there to help (Sandy was wonderful for me) If bub does not suck it is ok it is still early but even expressing a little and letting her have a lick can do wonders for your supply. While she is still laying near your breast get them to do the tube feed.
The closeness that both of you urgent is so beneficial, you may have to push a little, some nurses really encourage it, others are a bit more reluctant. The LC's are your best advocate.
I had a terrible supply with the pump, both bubs needed donated milk but once they could suckle things picked up and I BF for 7 months. Domperidone (motilium) did help my supply, again ask the nurse or LC and they can get the doctor to write a prescription which you can pick up from the hospital pharmacy.