This is kind of what I was thinking.If it isn't a very small breed, I would say no. But there is no way to be sure but to wait it out, I rather think there's something else going on. To be visible pregnant she would need to be two weeks or more along, and being fertile at 10-11 weeks would be highly unusual (I never say "impossible" with rabbits). Also second coincidence would have been necessary, a fertile buck.
As I said, I think there's something else going on. Please keep us updated.