Baby fussing at bottle between 6pm and 12am

niccole_15

My 7 week old, who is formula fed, has been having issues with evening feedings.  He will take a few sucks of a bottle and then fuss and refuse the bottle.  Last night, for example, he ate at 5pm, gave us his usual hunger cues (smacking his lips) at 8 and for 2 hours we battled back and forth of him taking a few drinks, crying, calming him down, and trying it again.  In the end he just fell asleep at 10:30 without even finishing an ounce (yes, we made a fresh bottle after an hour).  At 1am I heard him start smacking his lips and before he was all the way awake, I fed him and he took his bottle just fine.  

Here's what we've eliminated:

We switched from Tommy Tippees to Dr Browns- the minor gas issues we did have, are now gone.

I don't think it's reflux since he takes his bottles at all other times of the day just fine. 

We've tried gripe water, different temps (normally he takes bottles with room temp water), and pre mixing the bottle and heating from the fridge to eliminate the foam from mixing. 

Anyone else experience this?  Could he just be overtired?  Overly hungry?  Time to move up to the new nipple level?  

And speaking of the next nipple level- it says 3mo is the next step for Dr Browns, does that hold true or did you move up earlier/later? 

Thanks ladies!