You have a 'non-mating' Akita. This is common in certain lines of Akitas that have the genetic predisposition. They are physically unable to conceive. The downside of this is that they are also predisposed to endometriosis, ovarian cysts, and other reproductive tract problems. You should have her spayed IMMEDIATELY or you will have tons and tons of vet bills later. I'm glad you found out now!