<human>: My mom always had a problem with addiction, or so I was told. She got clean and had my brother, J, and I back to back. When she was in labor with me I managed to break her tailbone. They prescribed her heavy painkillers and thus, her addiction was back. 

So, in a roundabout way, I contributed to my mother's problems.

She left on Halloween. She left me at home by myself (13 months) while my brothers and dad were out trick or treating. I didn't see her again until my oldest brother, M, graduated high school almost five years later. 

Over the years she would randomly call, her mom would send us cards on our birthdays, and she sent me a congrats on graduating college card when I graduated high school. She spelled my name wrong. 

After experiencing what it feels like to be a mom, I was so devastated that someone could choose drugs over their child. I could never in my life imagine something so selfish or so evil. It made me question what kind of person I was which is stupid because I was a fucking baby (but hormones) that she would be so willing to just up and take off without her kids.

And now she's dead. And I feel terrible. I feel hurt. But, I'm also confused. I'll never get to ask her why. I'll never get to try and mend the relationship even if I had wanted to. I'll never get to introduce her to my daughter. I'll never get to say goodbye to the woman who didn't say goodbye to me.

I don't know how to feel. I don't know if I should go to her funeral. I would really like some help and advice if anyone has any.

Can you summarize the given text in a few sentences?
<bot>: my estranged mom left when I was baby and she died of a drug overdose. unsure how to proceed and how to feel.