I had the same medical profile as you - except my BP was very high (200's over 120 ish) not low. I had no headaches and only mild swelling. The thing my OB said about pre-eclampsia is that it is like lightening. One minute you are fine and the next minute it is there.

I was induced at 37 w 5 d and had a vaginal delivery. I won't say it was an easy labour as bub was posterior. Labour was hard and fast. I had an epidural to bring the blood pressure down so I could push. In the end with the assistance of a vacuum and an OB that is very committed to vaginal birth, bubs was born with no problems.

Let us know how you go.

Cheers,
Fiona