Sounds similar to what happened with Immy. Hers fell off on day 5 or 6 and for about a week or so after there were tiny dobs of blood and goo. We were a bit worried because it did look quite bad but the doctor (we saw him on day 7) assured us it was fine and just to keep it clean (we just used a bit of saline solution every nappy change and folded down the top of them to avoid irritation). Her belly button is now completely "normal" -- whatever that means!

Good luck for the weigh in!