Sleep regression? Help!

My daughter is almost 7 months old and has started waking up every 2 hours at night. She'll eat the majority of her bedtime bottle, but will REFUSE to drink a bottle when she wakes up through out the night. We cosleep, so I normally go fix a bottle and then come back to bed and lie down to feed her. She'll drink maybe an ounce if we're lucky and fall back asleep. Then she's up again in about 2 hours. I'm assuming she's waking up so often because she's hungry, but I can't get her to take more than an ounce every feeding. She's not sick, and she eats well during the day. This is so unlike her because she's only been waking up one time at the most since about 3 or 4 months old. Any ideas to get her to eat her bottles? Could it be something completely different? Help please!