Hi welcome to health care magic...
Usually
pregnancy test positive (if conception occurs) 5 week after last conception...
The both urinary HCG estimation and TVS
sonography positive after 5 week...
So wait for five days and than repeat both these test ....
If still pregnancy not there investigate with RBS and
thyroid profile to rule out diabetis and abnormal thyroid function...
Excess stress and
anxiety sometime can lead delayed period.
Reduce weight if you are obese ...
Heavy exercise avoided ...
Search for ovarian cause by simple USG examination....
Pelvic examination will also be useful...
Hope i have solved your concern....
Take care
Advise : gynecologist consultation