I told my mum I am not her therapist

Just some background info: I'm currently 17 in Year 13 and I aiming to study social work at university.
My mum has been an alcoholic for as long as I can remember which has lead to a strained relationship. Recently, there was a medical incident which led to her having to stop drinking. Since then, our relationship has gotten better however today just set it back completely.

I have been the person my mum chooses to talk about her problems to for a long time. This really messed me up as I grew up as I kind of had to be the adult in the situation. It doesn't help that her and my dad have a horrible relationship, still married but really shouldn't be. She would complain to be about everything, from my dad to her friends to our neighbours, and it was even worse when she started bringing up my dad's family and starts saying racist comments (she's white (easten europe) and my dad is south asian). this especially messed me up as she constantly mentioned that she "didnt want me to end up like his family".

She stopped drinking around 2/3 weeks ago and we were on pretty good terms but today she came home from her "friends" house (this is a whole other thing but hes practically her boyfriend at this point) and told me they had an argument.

This is nothing new, every so often she comes home from his place and complains to me that "hes so rude" "hes so controlling" etc etc, she even brings up his wife and daughter (messed up in many ways, and ill add that his daughter is around 25 but he does have older children, they just dont live with him)

Anyway, she was just complaining about him and I made some comments but overall I just brushed it off, I've just gotten used to tuning her out since it's never really a conversation with her, just her venting her problems at me.

I then went into the living room to have lunch and watch a movie and she started bringing up some other problems, like how she needs to find a job (she got fired around 2 months ago since she failed to show up too many times) and then she started mentioning conspiracy theories about Covid (she's really good at bringing up random topics).

Again, I really just tuned her out and so when she was done she went to the kitchen. However, I heard a noise that sounded like a bottle being open, a sound I'm far too familiar with, and so I went to the kitchen to see what was happening and she started making excuses for her drinking, saying "i need it for my mood" "im just so bored", and I forgot to mention but she's currently on medicine to help with her liver problems, yeah...

Anyway, I went back to the living room, she followed and started complaining again (I really don't know about what, I tend to forget what we argue about right after since I never actually listen) but I just got sick of it and I told her that I'm not her therapist.

She then mentioned the fact that I want to do social work and that I'll end up having to talk to other people about their problems but I was trying to explain to her that this and that are different things, she's my mum, I am not her little problem solver/listener, I am her daughter.

I then went to my room and I can hear her now complaining about me to her family or friends.

I know that I can get annoyed at the smallest things so I worry that I am causing these problems, sometimes I think if I just sat and listen then she would have no reason to get angry and we wouldn't argue but I just can't deal with her sometimes.

Posting this more as a vent but if anyone has advice or something like that, it would be nice to read. Thank you