Hi dragon, i know what youre going through. i think youre just a bit younger than me but i cared for my mom for the last 2 years of her life (along with my stepdad).
i think its completely normal to feel the things you are feeling - youre not mad at your mom but the cancer for changing your life and your families life. when a family deals with cancer (or perhaps any illness) for a long time, i think it can make the family sick as well. sometimes i found myself thinking things i did not really mean..when her odor would get so bad or she couldnt stop coughing or when she would try to talk to me and i coudlnt understand her and shed get frustrated, i would just ask god, 'why wont you just take her now!!?' Of course I didnt really want him to. It just breaks us all down at times.
you have to still do some things for yourself. i would go out with friends on a friday or saturday just to feel some normalcy for a few hours.
your mom would want you to do the same..every time i kissed my mom goodbye shed tell me to have fun and to not hurry back.

id give anything to do it all over with her again, every ugly minute of it. so please enjoy every second you have with her, whether it be good or bad.