Pre-eclampsia

Candance
OK so I just got a call from my doctor saying that ultrasound might show that I have pre-eclampsia. But the thing is when I look up all the symptoms of it with having swelling feet and hands. Then it says something about high blood pressure. Well I'm overly confused because my pressure is never high, I never have swelling. So I really Dont understand how I might have it. So of course I'm nervous as crap right now but my question is can anyone explain it a little better to me? And how come I Dont have any of the symptoms?