I need help, my dog is bleeding a lot from her vagina, does anyone have an idea of what it can be ?

My dog has been bleeding a lot like puddles of blood but she is not on her period because she just got off of it a month ago. She is a very active and energetic dog but now she is deppressed, she is not eating, and her stomach feels hard like as if she were blowded. She has been like this for almost a week, can anyone help me find out what is wrong with her?