Is bleeding when pregnant ( pregnat with period ) -the reason why bhcg test don't pick up ?

No.: If your HCG is negative and you are experiencing vaginal bleeding, then you are not pregnant; that is exactly how a miscarriage presents in the first few weeks after conception and many of them go unrecognized because women do not take pregnancy tests immediately after a late period. I am sorry for the bad news. Take Folic Acid 1-5 mg daily and keep trying!