Almost 3 month old refusing to nurse?


So my daughter is almost 3 months and she will have recent feedings where she just doesn’t want to nurse much. We are on an every three hour schedule for feedings. Most feedings she nurses and will get approximately 3 oz. I then follow up with a 1.5-2oz supplement of pumped milk or formula. I’m not able to not supplement at this time but it’s been helpful because then I at least know she’s getting the supplement which she will take. I will try to do a weighted feeding today just to see if she’s being more efficient. When trying to express milk to entice her I haven’t really been able to get much. I’ve also tried burping her, changing position, bicycle legs, and changing her diaper and she’s still refusing.

Any other suggestions or ideas of why this might be happening. She’s currently sleeping. Not sure if it’s a growth spurt?