I'm not 100% sure about the second question, but my bp had the exact same issue (except I don't feed her live). She's five months and stopped eating for almost a month after we got her. I took her to the vet, fearing the worst. They said she was healthy and gave her a shot and what I think was a pill. She ate for me last week, and was the most enthusiastic I've ever seen her. I would try that out if nothing works, but changing the mouse size might prove to help. You should also go back to the place you bought her and ask exactly how they prepared the mouse. Maybe try feeding frozen and then thawed. Just play around with it for a while. Don't touch your snake until it starts to eat again, and wait a while before trying to feed her something else. I don't know if it's proven, but I think they get used to the schedule.

Hope I helped!
Chris