Hi
Have you called the ABA? They have great advice for breast refusal.
Any signs of illness in your DD or anyone else in the house?
Has she started to crawl or anything like that?
Has af returned...?
At this age it is highly unlikely that she's weaning, but may be reluctant to feed for some other reason. I know you're worried about fluid intake, but it's best not to offer bottles if she's like this as that can help them along in making a switch.

It is really hard when they do this, but it's usually short lived if you can just relax and ride it out (and I know that sounds like stupid advice).

Have you tried feeding in the bath?
sometimes they're more amenable to feed when very sleepy and/or just woken up.
Are you offering or letting her come to you? Sometimes it helps to let them take the lead more (they like to feel in control about things).
If she's eating well, maybe she doesn't need it so often any more...

All the best~~