Olive oil should not be heated. Apparently it becomes a dangerours poison when we cook with it. Doctors and Nutricinists suggest we use sunflower oil to cook.
Olive oil ought to be used on salads or in any way but always uncooked.
What happens to you may only mean that you bought a second-class olive oil. don´t worry too much about it and next time buy a brand which yoiu know is good, even if it is expensive. Olive oil in plastic bottle does not sound good, anyway....
Broccoli is a great item in healthy food. Don´t give up on it! Your headaches probably had no connection with the ingestion of it.
Glad you´re only 22 and worry about being healthy!