Discharge before and after haidh
Q: I get my haidh for 10 days. But I get discharges before and after my haidh. I get discharges before 15 days of tuhr is complete then I get my haidh for 10 days (I bleed for about 5-6 days and I get discharges till the 10th day). After the 10th day I still get discharges. There are few days in between that I don't get discharges but most of the time I get discharges. My question is how do I count my haidh? I was told I have to count 10 days haidh 20 days tuhr and I must re-calculate from the 1st time I got my haidh as 20 days and 10 days, but as soon as I get a clean tuhr I will get my habit from there. I cannot recall having a clean tuhr. I was also told if I bleed during the 20 days even if it is after 15 days it will not be regarded as haidh but istihazaa. Only after 20 days will my haidh start and it will be for 10 days even if I don't bleed or even if I am clean (no discharge, blood, ect) what is the ruling? Is this 20 days 10 days thing right?