Exactly the same thing happened to me around the same time - my DS would hardly eat anything during the day, but would make up for it at night (a situation I'm still trying to remedy some months later!). I think it was related to a couple of things: Firstly a fast let down - my DS would freak at roughly the same time that I felt the let down reflex kick in. I consulted a lactation consultant and she recommended that I block feed for 3 days - basically, rather than switching sides each time you feed, you feed from the same side for a 6 hour period. This would tell your body that it's making too much milk. This had some success.
But I think position is the key. My baby is definitely a spirited type and when I feed sitting down, he's constantly pulling away to look at things and gets frustrated when I try to pull him back round. There were times I have to admit that I was trying to force his mouth on, not a good idea, cos then they get negative associations etc etc. Now, I take him into a my bedroom, pull the blind and feed him lying down and it works a treat. In fact he'll feed lying down even if we're out and about - you have to be a bit more creative as to where you feed when you're out of the house, but I've done it on a sofa in a restaurant, in the park etc.
If you lo is feeding well at night and you do it lying down then, maybe this would work for you?
Best of luck