Irregular bleeding

I am a 29 years old woman. I never had a fixed cycle since I got baaligh. Sometimes I bleed after 35 days and next time after 2 to 3 months. Sometimes bleeding continue for 4 days and other times for 6 days. I never know when will I bleed. Bleeding always lasts between 3 to 10 days, means it is never less than 3 days and never more than 10 days. After it stops it never comes before 30 days, but may not come sometimes even for 2 to 3 months. During the days when I am bleeding it also happens many times that I bleed for 3 days, then it stops completely for 1 to 2 days and then again few drops will come sometimes during next 2 to 3 days. I had 2 children, first time nifas bleeding continued irregularly for 55 days stopping in between completely for 3-5 days and then starting again. Second time nifas came 4-5 days only and then 1 or 2 drops used to come sometimes in a day for 20-30 days. This 1 or 2 drops was not coming everyday but only once in 3-4 days. Till now what I do is when I see blood I stop doing namaz and roza and when blood stops I bath and do my prayer. In my second nifas after 5-6 days I started praying and I used to bath and continue with prayers after this drop of blood used to come. Kindly advise me what I should do in this situation during haidh and nifas both please regarding salah, saum and intercourse?