We just got us a 90 day old lab and all she wants to do is lay around. What could make her poop blood when she really hasn't ate anything?

Take your dog to see a vet, she could have hook worms and this can cause blood to be in her stool, and also can cause severe anemia and death. Also there is parvo to worry about.. but a vet can do the proper test to make sure what her problem is. Seeing how she is lying around I would not wait long I would do it asap. Good luck

Those are not the classic signs of parvo, but it could be anyhow. If it is, the sooner you get her to the vet, the better. At least with a 90 day old, there is enough more dog there to have more reserves to fight anything. I think you need act as though it is the most serious thing it could be. See the vet.

Take your dog to the vet