Csab is right - you do get a shadow line where the positive result would be when they are left for a while, if you read the box this is why they say to disregard a positive result after 10 min. I wouldn't think its right but if your still unsure then wait a week and take another - just don't read it after 10 min.

Have you have the contraception injection before? Perhaps your body is having a bit of a delayed response to the injection - remember also that you only had a baby 3 months ago so there could be all sorts of reasons as to why you haven't got your period yet - worrying about it also can delay it.

Nae x