Really strange question for people who know about rabbit please help?

i have a lionhead rabbit that gave birth to 6 babies about a month ago but they all died straight away. i have gone out there today on the outside part of the hutch she has laid so much of her hair as if she is getting ready to give birth. she has not been with my male since the first mating over 2 months ago. so the question is... can a rabbit hold sperm from the male and get pregnant straight away.