Thanks everybody!
I HAD been thinking up to this point that she was just tired, because if I burped her and held her a bit, she'd settle down, and she slept through the night fine, so I wasn't too worried, just wondering what was going on.
However, after her barely nursing last night and being fussy, I tried giving her a bottle of ebm that I had frozen...she chugged the whole thing down so we gave her some more and she chugged that too. She slept in an hour later than normal.
I don't do a DF...she never woke up enough to eat, or woke up too much (she's spirited!), and she started sleeping through the night fine on her own so we just dropped that idea.
I know pumping isn't a true indication, but I tried it last night after she wouldn't feed just to see if it was a slow let-down problem or an actual amount problem. I could barely get anything out, when during the am it tends to just gush out.
This morning I tried pumping right after her first feed (so we'd have more to give her tonight), when I'm still engorged from the night, and got quite a bit out, but then for her next feed she was fussy again. So I'm wondering if I pumped too much. Poop.

Something else might have been the problem, though, because she wouldn't take a bottle either. I was just crying so hard, I've gotten myself all worried about this milk thing when she's been doing so well.
We have a friend that gave her los a bottle of formula at bedtime each night, so my DH is pushing for me to do that now. I know he's just being a man and trying to "fix" the problem, but I wish he'd share my desires to exclusively bf.
I totally don't want to try formula...I REALLY like the idea of pumping at night after she feeds to try to increase my supply. I will try that!
it seemed like my body sort of turned off milk making right around his bed time in anticipation of the night ahead with no nursing.
Hmmm...I hadn't heard of this before but I kind of wonder if that is my problem. I try to really eat and drink well, and everything seems good the rest of the day. I do cluster feed in the evening, but she always was fussy for both feeds so I always wondered if it was tiredness but now that she chugged a bottle down I'm thinking it's supply...