It is hard to not think about it. It is always on my mind no matter what I do. I am on the waiting list to have the IUD put in so hopefully when I have that I won't worry
Everyone deals with it in their own way and anything can be normal. I think if you are scared you should think about combining methods or trying another method that might be more effective. Ultimately though, worrying about something that hasn't happened may all be for nothing and it can be harmful to you to stress about it. I'm one to talk though! I'm upset when I'm not pregnant, and I'm upset thinking about getting pregnant and it not sticking.
I really have to learn to relax!!
I hope you can work through your worries.