Thanks for your query.
Spotting during the expected time of periods could be due to implantation
Urine pregnancy test done on the day of missed periods is 95% sensitive.
But, it is 99% sensitive when it is done 1 week after missed period.
You can also get your blood test
for beta HCG. Increasing titres suggests pregnancy.
detects pregnancy as early as 5 week(gestational sac
Hope this helps.