First of all, I am very sorry if you feel I am blaming you for any abuse you have been subjected to. This is not my intention at all. Abuse is never the other person's fault, never. I am sorry you are dealing with all the stress you have mentioned thus far. It is not your fault and you have no control of another person's actions. If you are currently in an abusive home please call a crisis center or find support services in your area. You do not have to stay in an abusive environment. If you feel it is not that abusive and you would like to stay that is your choice but you might want to do some serious work to ensure you mitigate the damages. Feeling extreme stress regularly can serioully impede progress in all areas of life. You do not deserve to feel extremely stressed often. Like I said the way your mother treats you is not your fault but unfortunately it is your responsibility to find the course of action that serves you best.
In a stressful situation we have three options: leave the situation, change the situation (we cannot change people only influence them possibly) or change your perspective. If you want to change the situation work on setting boundaries, asserting yourself, family counselling, communication techniques, etc. Again you cannot change your mother but you can change how you react to her which may influence her or not. If you feel you cannot influence her or change your reaction to her then it sounds like changing your perspective would be the next best option. This would likely require psychotherapy to get over any trauma. It sounds like you are already putting work into this so great work. It will take time to work through these feelings and it will be very hard when living in the same home. Just know you are not in it alone. We are always here to listen.
No matter what you decide to do know we do not judge you for your situation. Members here and I myself often give tips or advice when asked a question. If you prefer us to just listen (read) we can do that too. Whatever you find helpful is what we will work towards. We are in this together.
I ask because getting control of anxiety can very greatly depending on the person and their situation. There is not set time frame but if you have been working at it for a couple months and you noticed a little difference I would say keep working at it. If you have been working at this a couple of years and only notice a little difference I would say there might be something missing.
Figuring out what that is can be tough. I do note you often talk about the stress your parents put on you. You use very strong language around them (extreme for example). This gives a hint on your perspective on your parents. There is no doubt parents can cause stress on people, especially if abuse is involved. It doesn't sound like abuse is involved in your situation which is essential but it does sound like they are critical. You might want to focus your research on how to not let criticism effect you as this sounds like it's a big obstacle for you. What do you think?
Also, have you worked on desensitising yourself to the anxiety symptoms? This can be helpful in taking the power away from the fear.
Good luck and keep trying. Hope you get some relief soon.