If she is pregnant I really recommend watching a video by Victoria Raechel, she has a video on a accidental pregnancy and it is very informative.
If the hamster is pregnant make sure to remove anything that could harm the babies for example wheel.
You should also start seeing signs that your hamster is pregnant like: body looking plum-ish shape, nipples becoming more visible.
Here is the video I recommend:
https://youtu.be/6_v6ZWO177w