If she is lactating and nursing then you should be able to tell because the teets would most likely be obviously sticking out. Maybe you should take her to a vet to have her looked over and see what the vet says. They could tell you for sure if she is lactating or not. And then they could also tell you how to feed the kittens also should you need to. And if the kittens are nursing, the fur won't necessarily be wet, depending on when they last nursed. Are the kittens looking okay? I would probably see if you can't get the cat to a vet maybe tomorrow, the kittens are only going to last a few days if they aren't nursing at all.