All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The view which we adopt at Islamweb is that the minimum duration of purity between two menstrual periods is thirteen days. Please, refer to fatwa 210271. Therefore, the bleeding which you have experienced after eleven days is not considered menstruation; rather, it is Istihaadhah (vaginal bleeding outside the menstrual period).
According to the view adopted at Islamweb, you should consider the length of your regular menses and regard any bleeding that exceeds it as Istihaadhah.
If you do not have regular menses, then you should distinguish between menstrual and non-menstrual blood. If you see what you distinguish as menstrual blood (by identifying its characteristics, such as the blackish color, thickness, the usual smell, and accompanying pain), then you should consider this as menses and you should consider what exceeds it as Istihaadhah.
If you neither have regular menses nor can distinguish menstrual blood, then you should count the menstruation as 6 or 7 days when you first see the blood and consider it to be menses, and any other bleeding is considered Istihaadhah.
After the passing of the days which are counted as menses, you should perform Ghusl and then perform ablution for each prayer after its time becomes due.
This is the view which we adopt in our fatwa, and it is the view held by some researching Hanbali scholars. We do not adopt the Hanafi view in fatwas on our website.
Allah knows best.