Same happened with Ds. I was really worried about it being infected or heamorage etc. I rang the baby helpline and they said it was normal. They said to gently clean the area around it with saline (boiled water with salt and then cooled to room temp) and cotton tip.
His was a bit green and slimey and slight smell and was coming off early too. I did what they said and when the midwife came to visit 2 days later she said it was normal too.
Ring the free helpline too and explain how old your bub is etc and see what they say to give you peace of mind. If it sounds to them like its not good then they will tell you and you can get help from there, but I think it probably is ok.