Have had pms symptoms two weeks before period. now suddenly my symptoms have stopped. period due in a day or two. what causes the sudden lack of pms?

PMS symptoms: "PMS" is caused by sudden drops in estrogen, as in just prior to ovulation and just prior to one's menstrual period. This does usually not occur prior to ovulation unless two eggs simultaneously are matured, and the estrogen "drop" is magnified, giving rise to PMS symptoms, which vanish as the estrogen production is resumed after ovulation.