It could possibly be a sign.
To be absolutely sure, the best thing to do is wait until 36 days after she was last with the male. Even very experienced breeders have troubles palpating or finding signs of pregnancy. So the best way to be sure is to just wait, preparing for the birth regardless.
I would give her a box with lots of hay, and about an inch or two of shavings in the bottom for her to make a nest in. She should start stuffing her mouth with hay and building a nest. Some buns will make several versions of a nest and keep rebuilding until they give birth. Others will wait until just before or as they are giving birth.
If she doesn't give birth by day 36, then she wasn't pregnant. Then you can look into getting her spayed and the male neutered, and there is a good potential that they will bond again.
However, if you get the male neutered before getting the girl spayed, be aware that he can impregnate her for up to 8 weeks after his operation. So they have to be kept completely separate until 8 weeks after his surgery.
--Dawn