All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
There is no doubt that the mother has a great status and the Islamic Law gave her a great consideration and enjoined the children to be kind and dutiful to her. Allaah Says (what means): {And We have enjoined upon man [care] for his parents. His mother carried him, [increasing her] in weakness upon weakness.} [Quran 31:14]. Her right is that a person should be kind and dutiful to her and be patient with her. Even if she mistreats her children, they are not allowed to mistreat her, or else they are considered as cutting the ties of kinship with her and are committing one of the grave major sins.
Therefore, we advise you to take the initiative to repent for mistreating or humiliating your mother and you should ask her to forgive you. Furthermore, you should supplicate Allaah for her goodness. Allaah Says (what means): {And lower to them the wing of humility out of mercy and say, “My Lord, have mercy upon them as they brought me up [when I was] small.”} [Quran 17:24]. For more benefit, please refer to Fataawa 82254 and 84624.
Your mother’s saying to you ''I am not your mother'' does not justify you saying "Am I expected to accept her motherhood'', as this is a misconduct with her, because she is your mother and you are obliged to be kind and dutiful to her whether you like it or not, and even if she mistreats you.
Allaah Knows best.