Is my hamster pregnant?

Sunshine, my robo hamster, was with a male robo a few weeks ago. (They're now seperated) She's gotten fat and loves to hoard food. I havent tried breeding robos before, but had experience w syrians. What worries me is I saw blood in her bedding. Is this a cause of pregnancy? Is she pregnant? She doesnt look sick, she still runs in her wheel and eats ok.