Did I poison myself by eating popcorn made in a steel pot with olive oil?
Olive oil has a notoriously low smoke point. If you're looking for something nutritious to pop corn with, try avocado oil.

While burned food tastes yucky, and there is (some) evidence that a steady diet consisting mainly of burnt olive oil may be (slightly) carcinogenic, it is highly unlikely you did anything worse than ruin your munchies.