thanks for the query,
Failure rate of birth control pills ranges between 0.2-1.5.
Bleeding on Jan 30 could be implantation
bleed followed by threatened miscarriage
I recommend you to get a urine pregnancy test followed by Ultrasonography
to be more sure.
If UPT is negative, Wait for 1 more week and get your hormonal levels checked.
It could be dysfunctional uterine bleeding
Hope this helps,