The end of the PhD can be an anxious time. If you’re worried, or unsure, or feel like an impostor, then you’re the person who needs to take action.
You don’t have to face everything alone, but you do have to face it. Don’t forget that there are people around you that you can ask for help. If you don’t need help then figure out what you’re going to do, and get it done.
Doubting if you’re ready isn’t enough. Thinking about why you have doubts isn’t enough. You have to work your way out of the situation.