I had HELLP at 37 weeks with my last pregnancy. My daughter just turned two and I am currently 34 weeks with a boy. Believe me, I have been pretty paranoid this whole time! However, I'm feeling very relieved to have hit the 34 week mark.
When I got pregnant this time, my doctor had a plan in place for me already. The first two trimesters were pretty much the same as regular pregnancies, but starting at week 28 I've been doing regular labs to check for kidney and liver function, platelets and protein. I'm now going in twice a week for non-stress tests and I take my BP at home regularly. Unfortunately, these things can present so suddenly that this may all be pointless in giving us any warning, but it's better than nothing.
I'm sure you already know this, but HELLP (and I think PE, too - I didn't have PE) are more common in first pregnancies, especially if the dad is the same. So you've got that on your side! What week did you develop HELLP and PE? If recurrence does happen, it's typically around the same time as the first.
Best of luck to you!