Why are other moms so caring?

my mom is single, and me and my now 19 year brother were basically her "helpers" all her life, we were like a team, if my mom could not pay the bills, my bro and i would go find babysitting or mowing a lawn to help her out. She treats me good somtimes and i know she luvs and if she had the money would probably let me do anything and no i dont think she uses us cuz it was hard for her to take care of us but she has gotten so mean lately(the past 3 years)(she is 41 btw) and when i tell her i have had a bad day at skool, she says "ok, well i cant help u" in a sarcastic mean voice that i HATE! when i clean up the house, she doesnt say a WORD unTIL i say hey i cleaned up and her common answer would be " u didnt! look over there! thats not clean!" i mean does it HAVE to be perfect???!! when i tell her my feelings like "could u be a little more appreciative and nice?" in a calm nice voice, she yells at me and throws things(tv remote, cup, watever she can get her hands on) usually she says "im the mom, the master and i can do watever i want!" and we are CHRISTIANS for petes sake! i mean, she doesnt wanna listen to my feelings and when i say "you hate me!" she says "if thats what yuo want to believe" and she says it in a sarcastic MEAN VOICE that she KNOWS drives me nuts, and no! this is not a 'bad day'. we do this practically EVERY day, i have NEVER gone a day without crying becuz of her! i dont think i could LITTERALLY, SERIOUSLY tell u ONE day i havent cried cuz i seriuosly have cried every day with her, even when i am gone, she wll call me and say somethin negative, like "did u steal something from me???". and i cry cuz im being screamed at by my D*m mother over the phone! i wanna be a good christian and have a good heart but i truly feel she is preventing me from doing that without knowing she is. i truthfully dont think she knows shes wrong. Have you ever had a mom that tells u your bad, and u can admi u r sumtimes but she never admits SHE`S wrong. i understand she is my mom and i should respect her but no one ever believes that behind closed doors, she is BAD and i could neveer tell on her cuz 1. i will get in trouble and 2. like i said we r a team yet i feel she is seperating from the "team" cant she just be happy without bfs, txting, and drinking??? BTW IT ALL STARTED WHEN WE GOT OUR FIRST COMPUTER, ever since then, she acts like a teen and txts ppl all day, she used to travel ALL the time, we hated staying home and wasting our lives like other familes by buying toys and tech stuff all the time. we ARE country and i really miss that old "no technology team work country life" it was definetly the life for ME. ......):