I wouldn't say it is unusual for children to "backtrack" so to speak over potty training. Don't be alarmed.
Look at the events before the past week. Has anything significant happened or changed? Something stressful might be at the root of her regression.
I have a 7-yr-old boy who went for months without wetting the bed at night. When he started wetting the bed again, usually because he didn't go to the bathroom "one more time" before falling asleep, and when I got tired of changing and washing sheets, this is what I did. I went to the store and bought a package of "pull-ups" for bigger kids (I found "disposable pants for 85-125 lbs kids!).
Then I had him wear his new "nighttime underwear". He kind of had fun the first night but complained that they itched and weren't comfortable. Well, I then gave him a choice. Either he went to the bathroom (and "at least tried") right before bedtime or he put on one of the "new nighttime underwear". I even let him wear his regular underwear underneath (since it was the sheets I didn't want to get wet!). Then, I would let him resume wearing just his underwear at night. When he wet the bed again, I told him he had to wear the "new nighttime underwear". That would last a night and he hasn't wet the bed again.
I'm not saying it would be that quick for you and your girl but it's something you might try.
From what I've heard, you should emphasize that this isn't a big deal. Make it matter-of-fact and keep the rules simple.
After that advice, take what you think could work for you and your child and leave the rest! Follow your heart and mothering instincts!
Good luck!
D.