Overdue test negative

Hi there, I have a question. I'm 6 days late and haven't been too focused on trying to get pregnant. However, I think I've been off the pill for about 4 months now. I usually get my period right on time, but not this time. I've done quite a few tests and they're all negative! I also spoke with my GP, who said there's probably nothing medically wrong with me. (I was worried it might be a health issue.) She told me to test again in 10 days, and if it's still negative, I've just missed a period. But I've never had this happen before. Last month and the month before that, I had much less bleeding than usual during my period, and now suddenly nothing at all, and I'm 6 days late. I'm not sure what to think. I don't really have any symptoms either, no period pain. I do sometimes get a stabbing sensation in my hip and pubic bone on both sides, and I even had a sharp pain in my liver area for a moment. Could it be that, as my GP suggested, I might still get a positive test in a week or so? I got the feeling that the GP was just saying those things to reassure me! I hope someone can tell me more and help put me at ease. Love.