I am having irregularity of menses for last 1 year.I bleed off &on almost daily.Could you please tell me can I offer prayers & can do fastings in all the days excuding menses days.

Asalam-o-Alaikum,before 1 year my cycle was regular &my habits were that I usually bleed for 7-9 days & then a gap of about 19-22 days(without any bleeding)i.e the average duration of my cycle was 28 days(+_1 or 2 days).I have read about istihaza in your website as well but after the 15 days ,you have used the word"Tahara". (1)So please tell me,can a women offers prayer & do fastings in Tahara phase (like in istihaza phase),just after making wazoo before each prayer.If the rules are different for tahara phase tell me in details,Can I do fastings in these days & what I need to do to offer prayers & recitation of Holy Quraan in Tahara phase. (2)further more as I read from your website that the cycle can be short like of 22 days(shortest).Iam counting days of my cycle as previously ,like 28 days cycle . because bleeding becomes heaviest for 3 days & give me the generalized feeling of unwell during these days,same like during menses days.so I am counting these days as a True menses days.Am I write in doing this ? I would be grateful if you can clarify to me all the rules & regulations according to my bleeding schedule. JAZAKALLAH.