Oh aak0517 I'm so sorry that happened. There's nothing worse than someone you love dearly hurting you like that. I'm in no way minimizing the situation since I don't know details but sometimes we take things out on those that we love because we feel 'safe' with that person with our feelings. Even if that's not what we realize we are doing in the moment. Perhaps she feels 'safe' with your love and needed to vent but it came out in a really wrong way
As far as feeling like you're not measuring up, honey, you are beautiful, smart and clearly doing life very well. Don't be so hard on yourself. As a mother I can see how my own hopes for my children to be 100 times 'better' then myself would easily get away from me. I can understand now how a mother could project that onto her daughter. Head up my friend, you are ALWAYS ENOUGH.
"He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion." - Unknown