Been on yasminelle bcp for 4weeks now and my period started after 21 active pills, but it is not stopping, after 10 days.

Can happen, monitor: Irregular bleeding is the most common side effect in the early months of pill taking. It is more of an annoyance rather than a serious issue. So if tolerable, monitor, continue the pills as directed and hope for things to settle down in 3-6 months. Certainly, if the issue is really bothersome, consult with your provider as to what the next step should be, or arrange an inbox consult with HealthTap