Hello Codybear, and welcome to the board! I am so sorry it took me a full day, almost two, before I could respond to your post. Doing my best to make amends to you, now that I have some time to devote to a thoughtful response.
I didn't have the same experience as you growing up (different generation, different experiences) but I have witnessed a similar situation with my two sweet young (great)nieces. Let me tell you their story, and how they survived it:
My nephew (nearly the same age as me) and his wife both dabbled in drugs a little when they married, and for a few years after. When baby #1 came along, they quit - cold turkey. Baby #2 followed two years later. Their mother somehow decided that #2 was the last one, so she was now free to enjoy her drugs again - and she did. My nephew did not - and the arguments and fights began.
His wife stayed out all night sometimes, then that grew to leaving for the entire weekend. She began stealing to pay for her habit, and even turning tricks on the streets. My nephew had all he could take, so he left. Sadly, he felt his own previous drug history would prevent him from getting custody, so he left the girls with their mother and moved to the midwest to clean up his act.
For a few years, as far as we can figure out, the girls and their mother lived on the streets of L.A., homeless most of the time. Begging food and money on streetcorners, sleeping in cars or wherever they could beg a bed. the girls told me how they played with drug syringes as squirt-guns, going days without food cuz Mommy was 'sick' and wouldn't wake up, and watching their mother being beaten and raped - repeatedly - while hiding in the bathroom or under the motel room bed.
Anyways, a short court process followed and my nephew was awarded full custody. The girls arrived at our airport malnourished, pale, scared, clinging to each other - dependent on each other - at ages 6 and 8.
Their mother supposedly sobered up, and followed to our state to clean up her act - so she could be with her daughters. She got a job and a place to live, but it wasn't long until she found new 'friends' with the same old lifestyle, and she was back on drugs again. She's now serving time in a federal pen for accessory to kidnapping, armed robbery, and assault. She's also suffering a terminal liver disease, related to her drug abuse. She'll be out on parole in a few months, but isn't expected to live long.
The girls are now 15 and 17. They are still suffering each in her own way - the older girl is dealing with some identity issues, and I think feels guilty for her mother; but the younger one is having a harder time of it - still cries often, refuses to talk to or visit her mother, and acts out in some pretty astonishing ways. But they're doing VERY well, considering what they went through, and preparing for their mother's release from prison. They do have a loving and supportive father (clean and sober 17 years now), doting grandparents, and me, involved in their daily lives.
they don't suffer anxiety like you do, but I worry: The older one craves attention and love, and I worry she'll seek it from the wrong people; and the younger one - well, I worry even more for her ability to open up and bond with others at all.
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I am so happy to hear how you're dealing with the traumas you experienced - you sound wise beyond your years. It's wonderful that you realize your mother's addiction and problems were HER problems, and not yours - then or now. I've seen friends and others lose themselves in abusive relationships with SOs and have never truly understood why they stay with these men. Perhaps one reason she stays is because of her addiction - he supplies her habit, and without him she's afraid she won't be able to survive.
I know it's possible for addicts to overcome their addictions, but they have to reach a point where the ONLY way to survive is to overcome it - and admit their problem, then seek help on their own. they have to want to quit, else they never will. Do you think it's the same situation when one stays with an abusive SO? Like an addiction they will never overcome until they choose to seek help?
You said "letting go is the only way to be free"... perhaps it's the same with your mother.
Sorry, I'm rambling on and on... probably not making much sense. I just wanted you to know you're welcome here, and I hope we can help you on your journey to healing. Sounds like you've come so far already - but still have a way to go. How do you deal with the anxiety today? What helps you the most?
Keep us posted on how you're doing - there are lots of people here who really care (I'm one of them). We may not have miracle answers, but we have loads of support and understanding.
I'm glad you found us.
Love 
