I have a 12 month old dane that has ben out of her heat for about 8 weeks now. She shows no signs of putting on weight, yet her nipples are bagging/drooping as if they have fluid in them. She has not shown any other signs of pregnany either. Any idea what is happening?

Sadly I'm not sure. Time to go to the vet.

Is pregnancy a possibility? Has she been in contact with a male during her heat cycle?

While you're at the vet make an appointment to have her spayed, she's old enough.

Good luck.

I agree with Alty, we cannot tell you what is wrong.
You need to go to your vet for a proper examination.

My suspicion would be a phantom pregnancy... Sometimes dogs will think they are pregnant and even have changes in their body without actually being pregnant.

Has she been under supervision her entire season? It is possible another dog got to her and she may in fact be pregnant but not carrying many puppies (which would explain no weight gain)

I had a bassett hound that every time she came in it seemed... she would have false pregnancy. Took her to vet many times to get "dry-up" pills.