Respecting and obeying one's mother

Q: I m very disobedient son of my mother, and she stays unhappy with me, i always try to be good and be obedient but sometimes i loose control over myself and do things which she hasnt allowed me. Today i said a deep sorry to her and made a dua for forgiveness as well, i want to be an obedient son, so i can be successful in life and make my mother happy. So what can i do? Is there any special way to keep god control over myself or any wazifa that will make have god control over myself and be obedient.

Taking the name of Allah at the time of adultery

Q: This question is very important. In fact, almost all committing this sin face this, but do not think about it and do not ask about it. Will this be a kufr to watch pornography and masturbate, in which actors pronounce the name of God during adultery and/or they utter phrases that offend God, during adultery? Will this be contentment with unbelief and with an insult to God, if muslim does not agree with these words and actions in the heart?

Calculating haiz when in istihaazah

Q: In the case of istihaaza, if my period starts at around 4:00-5:00, then after my haiz days I then count 15 days as clean, now I am still having discharge like 2 times a day. So if I see any discharge at approx 4:40,will my haiz start? This is because I dont know the exact time my haiz had started last time, it was around 4 to 5 o clock... So it could be after 4:40 also.

Is it important that my counting should go in exact hours and minutes or can there be a difference of half an hour or so? I have counted the above scenario as my period. Is it okay?