It's clear you're concerned about your daughter, and it's understandable. It's great that you're taking steps to understand her better. Some of the behaviors you described, like seeking reassurance and having specific rituals, could potentially be signs of OCD or other anxiety-related issues.
Booking a doctor's appointment is a good move to get professional guidance and a proper evaluation. Remember, you're not failing her; you're actively seeking help and support, which is a loving and responsible thing to do. Besides, there's a lot of info OCD. You can learn this here now.