No need for extreme anxiety levels here -- this is not at all uncommon, especially in flat pelvic type cows. Dairy breeds will pool urine routinely due to the loose loins they normally have.
Most cows who do this will be pretty flat topped, meybe slighly high in the pins instead of slopeing off some.
There are concerns however, a cow or two every so often will tend to get a pretty severe vaginitis -- vaginal infection - from the extra fluids. They usually just drain when ever they lay down, and will only pool urine or other fluids when up walking. If they get a bad enough infection, early in gestation, it has been seen to cause an infection inthe cervix as well, and then the possibility arises of an abortion. This is very uncommon, but does happen.
I would guess that she did not just suddenly start to pool urine this month -- she has been doing it in previous years as well, it just doesn't suddenly happen.
Describe your cows phenoype and I would be surprised if she was a slopy butted cow, but more likely level or even slightly loose in the loin. Again, not at all uncommon -- no need to go on Paxil just yet.
Take care and good luck