Untrained Rabbit Behavior

I've had my rabbit for 1 year. She is supposed to be a female but she's acting like a male. She was so good in the house but she suddenly started pooping and peeing and I'm frustrated! She isn't litter trained and I don't let her out of her cage when I'm not home, but she never went on the floor. I feel awful cause I can't let her out anymore and she's stressed. Is she maybe a male and marking his territory?