She sounds like she's getting closer to having that calf. Not uncommon to see the clear goo a week or so prior to calving. Most of mine start to lose the mucous plug a week or so before they calve. I don't always go by their udder filling. I have a few who don't get a 'bag' until they actually calve, a couple bag-up the day before , some a week before.
Sounds like everything is going as it should. Cows can and will calve anywhere from 2 or so week prior to and 2 to 3 weeks past their scheduled calving date.
Katherine