This might be a useful place to start. If I was in your position I'd read it and then make an appointment to see your GP to clarify the bits that you don't understand. This might help settle your mind while you wait.
Giving the BCNA helpline as suggested above is a good idea. It's staffed by nurses who can help you decode.
I had my mammogram on the 4th Novembet last year. It was three weeks before I received my callback letter. Don't stress about the wait more than you can help. If they see something truly urgent you'd be seen immediately. K xo