Don't know what to do about 3 month old baby's feeds? Can you help?....?

My baby boy is going to be 11 weeks old on Thursday. The problem I'm having is I'm not sure if he's getting what he needs from his feeds because he's still asking for them every 2 hours. He's not really changed his pattern at all from birth apart from now taking more feed. He was born 8lb 11oz and now weighs 14lbs so he's doing well there. It's just he wants feeding every 2 hours, day and night, so he's having 12 bottles in a 24 hour period. He now has 5oz (150ml) in each bottle, sometimes he takes it all, sometimes he leaves about 20 or 30 ml in the bottom, he won't take any more than the 150ml at once. My husband works away and so I'm on my own and it's really starting to take it's toll on me now. He's on Cow and Gate comfort, which really settled his colic and seems fine for him, but I can't understand why he's not going longer between feeds, everyone I speak too have babies which went much longer than this at this stage. I can't understand what I'm doing wrong. Because he's quite a big strong boy people have told me to try a tiny bit of baby rice before bed to keep him a little fuller but then others say you should never do this (I had a tiny spoonful of baby rice from 3 months and was absolutely fine). I just want him to be a little fuller and don't really want to change his milk again as it upset him last time. I'm not sure what to do, I'm so exhausted now. I feel like I'm doing things wrong.