Night sweats early pregnancy symptom?

Julie • Married in `04. DD `05 and DS `09. TTC #3! I`m 33 till 10-15
AF is due 10-9 and the last four mornings I've woken up absolutely drenched. I'm talking the sheets are so wet it's like someone poured a glass of water on them. I've never experienced anything like it before. Has anyone heard of this being an early preg sign? Sorry if TMI.