TWW Paranoia 🤦🏼‍♀️🤦🏼‍♀️🤦🏼‍♀️🤦🏼‍♀️

When exactly does your tww start and end? When do you start taking pregnancy tests? What are brands that pick up the earliest? I’m nearing what I believe is my tww but I don’t want to test just Incase I’m too early so I don’t make myself crazy!! Help!! Thank you!