Hi A.!
Bottlefeeding and breastfeeding require very different methods of sucking. Bottlefeeding requires more "sucking", as if one were to drink out of a straw, while breastfeeding requires a more "kneading" or "massaging" of the nipple/areola -- this type requires a whole different set of muscles for the baby, and usually more effort, too. The baby may prefer one over the other. Often babies prefer the bottle, only because it requires less energy of them. However, as in your case, breastfeeding may be providing your baby a more intimate feeding experience with you where strong bonding is sure to take place. As for the amount of milk your breast is producing, you need to TOTALLY breastfeed, even if it means feeding every hour for the first few days! Sounds crazy, I know, but breastmilk is supplied on a supply/demand basis. The more baby nurses at your breast, the more milk will be produced. Also remember to drink plenty of fluids, eat well, and try to get as much rest as you can in between feedings to guarantee good milk production. Good luck with your new baby!