Maddy, I can sympathise as I am in exactly the same position.
One lambed in the early hours of Tuesday morning although she hardly bagged up at all beforehand.
There is another who was due before this one and although fairly big isn't showing any signs of giving birth yet. We are also up all hours checking. It may be that, although she was raddled, the ram didn't get her the first time but may have done so in the next cycle. Having said that I would be surprised because of her size.
I have been told not to worry until a few days after the ram came out.