My little one was born 7 lbs 3 oz and is only weighing in at 8 lbs 7.5 oz at her 2 month appt. We feed her every 2-2.5 hours and give her as much as her little tummy can hold. They have us giving her supplementation formula about once a day but she hates it so I mix it with my breast milk in her bottle throughout the day. The pediatrician actually asked us if we are feeding her when she's hungry. I was like no, I'm starving her. Seriously?! She's so happy and playful and hitting all her milestones (minus the weight of course) and has a belly you can't see her ribs or anything.