I have an extreme cough. Is it whooping cough? How can you tell that from regular bronchitis?

Not likely. Children in us are vaccinated against whooping cough. The cough has a peculiar sound- whoooop.
Requires culture of. Secretions from nasopharynx to make a positive identification. A good number of adults and teenagers are actually experiencing whooping cough instead of "bronchitis" while they are having prolonged cough. It's no surprise that adults and tennagers are the main source for the whooping cough in infants.