I'm so upset.

I can't believe this happened to us.  Growing up we believe my Dad's love for us would never change no matter what.  Now he's chosen to side with my step mom to the point where he doesn't even want to see us anymore.  He used to be so balanced and cool, and just the right amount of strict, we think the sun and the moon of him and we thought he returned the sentiment.  I really tried to like her.  I was so happy for my Dad for not being alone.  I liked her even before I met her.  However, she started to chip away at my respect like a wilting rose in the fall breeze.  Amongst her many transgressions are things like, drinking and driving, kissing my best friend, belittling my father behind his back, I have a suspicion she's spending his money, bashing us behind our backs, she's an alcoholic in the true sense of the word, she's incredibly crude and ill mannered, everything she owns is plaid and from walmart which she loves to brag about. she tells my Dad that we are selfish and inconsiderate creatures who have the worst of intentions.  He eats up every oily word.  I lived for my father's praise.  I judged my self esteem based on his praise of me.  As an adult I took up shooting to be close to him, I watch old movies because we watched them together.  My father made me feel like I was his little girl and he would have my back forever more.  That I was a good person and did well for myself and that I am intelligent and moral.  My brother felt the same.  We were the three amigos and no one would ever come between us.  As it turns out all it took to brake that bond was a woman whispering nasty little nothings.  What shall I now believe?  My idol just told me that I was always a selfish, inconsiderate, bad person.  It's like finding out santa clause is a child molester.  I feel half gone.  I can't get my bearings.  I'm so messed up right now.