Tit tit is pregnant?

I wonder is my girl hamster pregnant. Her tummy grows bigger but I can't find any other symptoms that prove she's really pregnant. Hmmm.. Everything is still the same, she runs, she sleeps, she eats a lot as usual.

My dad ever had white mouse as pet when he's young so I asked him about it and he said she's pregnant. Actually I didn't know he had a pet mouse before till he told me just now. I just know he likes animal very much and can be friendly with them. You'll never imagine how cool he is! He can even play with his pet fish. 

Btw, I'm really happy if Tit tit's pregnant as I really wish to have a chance to see how animal raises their youngs. I'm soooooooo excited. Hopefully she's really pregnant if not I think I'll feel disappointed! ><