Anyone get a low number blood test and later test positive?

I am now 6 days late. I am never late. I took a blood test day before yesterday and it was only a 1. I emailed my doctor to see what next because if it is negative then I would like to be able to start my next cycle and chlomid. He wants me to wait till Monday and take another pregnancy test before prescribing progesteron.

Has anyone experienced this before? And what really is the likley hood that I get a positive on Monday when I am already late with a negative blood test? I was very hopeful up till day before yesterday, and to be honest I am a little down at the moment, and try to dare not hope at that little possibility. Has anyone experienced this or know anyone who has? Thanks