I have a female that was pregnant and I separated her from the male roughly 5-7 days before she was due and placed her into her own tank, where she has remained throughout nursing (male has remained happily in his own tank). She birthed 7 healthy pups (4 black, 3 agouti) and all eight did great. They're slightly over 3 weeks old (3 weeks and a day or two) and I noticed tonight that she's getting heavy like she's pregnant again. Is this possible? The reason I as is that I was told by a friend who breeds mice that he had a female that would produce two litters from one breeding roughly a week apart due to her having two uteruses.

She hasn't been around any mature males for about a month, and any males in her litter would have been too young to have done anything for her to show this kind of development. The only other possible thing I can think of is tumors, in which case she'd have multiple ones since I'm feeling several lumps. As it stands, I'm seriously considering pulling her away from her pups since they're all eating solid food and drinking from the water bottle in the case that she is pregnant (Don't want her to stress out or anything).

I'm basically wanting some additional opinions before I make a choice.