Post partum preeclampsia can occur up to 6 weeks post partum. Blood tests can change in a matter of hours and I see it's been a few days since you were tested. With a headache, and high pressures on HBP meds, as well as swelling, I'd get in for a repeat of blood work. Ask to see the OB or Perinatologist on call, not just the ER doctor. Post partum preeclampsia is very scary, so please be seen. Better safe than sorry. They can treat your symptoms aggressively since you are post partum. Keep us posted.
Sometimes it takes weeks to get back to normal, but you should listen to your intuition and your body.