Are you 100% certain she is in a heat cycle? Let's hope that is all it is. If it were my dog, I would take her to an emergency clinic to be sure it isn't pyometra. If it is pyometra, she won't get over it, it will kill her. The fever is especially troubling, I don't think that dogs in a heat cycle get a fever?
Pyometra:
Pyometra & Uterus Infections in Dogs