Hi and welcome to the forums. I can definitely relate to your concerns, I also have a history of preeclampsia close to term.
During my third pregnancy last year I started out with chronic hypertension, and my OB said that she was comfortable waiting to induce at 38 weeks as long as everything stayed the same. However to plan for delivery at 37 weeks if pre-e struck again (ie my proteinura came up). My MFM recommended induction at 37-38 weeks based on my history of pre-e.
You could ask your doc about the HYPITAT study
("Hypertension and Pre-eclampsia Intervention Trial At Term") which found an improvement in maternal outcomes with induction at 37 weeks for hypertension or preeclampsia without a difference in fetal outcomes. And see what their opinion of the study results are.
You could also ask about a repeat 24 hour urine test this week/weekend to see if your protein levels are trending up. The tests are fairly cheap and a repeat might give you some (temporary) peace of mind or it might give more weight to delivering sooner. Did you happen to have a baseline 24 hour urine done in early pregnancy or before pregnancy to compare last weeks results to?
Are you monitoring your pressures at home? How often are your appointments now?
Also please take a look at our Signs and Symptoms
page if you haven't already, and please don't hesitate to call your doc or head in to L&D if anything feels off.