I understand that people worry and I understand that if something bad happens to us it colours the way we see and feel about things, and I am sorry that you have had that experience, but I'm afraid I feel like I need to say that the way you reacted to your daughter is not okay.
She's 8. She won't understand that there might have been a threat, and to be honest it doesn't really sound like there was one. What she will remember however, is that her mummy screamed at her and she won't understand why.
I think it would be a good idea for you to try to deal with whatever is causing you such upset and worrying you about your daughter, because as she gets older there will only be more situations for you to worry about, and you will cause yourself and your daughter more upset by not trying to address it as soon as you can.
I don't mean to belittle anything you have been through, but do feel strongly that it is important for your daughter and for you that you do something about it.