Respecting one's mother

Q: I always have behaved badly with my mother. It is from my childhood. Now I know it is a grave sin but after doing tawba so many times I cannot change myself. I always have negative thoughts about her instead of her favours to me. I always think about the bad side about her and disrespect comes in my mind for her. I have tried but cannot get rid of it. I know she has many faults in her for which I disrespect her in my mind but this is a grave sin. How do I get rid of these thoughts and treat her with utmost respect?

Qadha for missed fasts

Q: If I have not kept many fasts without any valid reason in my childhood, when I became baligh how do I fulfill it? Do I have to make kaffara? What is the kaffara and what if the amount of fasts is so many and I don't remember? 

Balance between ibaadah and social life

Q: How do I balance between ibadah and everyday life? When my sisters come they complain that I don't give much time to them.. I also feel it difficult to go to someone else's home and fulfill my regular amal as it takes so much time..I also fear after marriage I will not be able to continue these aamaal as there will be so much responsibilities.. so what should I do?