Argument with my mum

Backstory: I'm the oldest of 4 sisters and am turning 18 later this year. I have a love and hate relationship with my mum and we've always fought since I turned 13. My mum had me when she was 19 so we mostly have a playful relationship although at times she decides to act like a mum at random times which we've fought about many times before, because I can't keep up with the change. I do have a close relationship with her I usually always talk to her and can't stay angry for long after arguments.

So I've had an argument with my mum over a dumb reason over a week ago, so basically I ended up doing a pastpaper with my teacher during the last half hour of a class since we finished our work and didn't have anything left to do. I mean I had no problem because doing a pastpaper will always help especially since it was in a subject I was weak in.
To sum it all she wasn't pleased and said I was wasting money and a lot of other mean things. I obviously got offended and argued back, although I didn't say anything mean I just cried since I got angry and tried to defend myself. My dad was present but he's always on my mum's side and was just annoyed and told us to basically stop and shut up. We argued a bit more and then I just left to my room.

Later that day she started fighting again this time about me doing a 2 hour class when I should be doing a 1 and half hour class, but I've been doing a 2 hour class for more than a couple of months. I once again cried and ended up raising my voice because I was emotional but didn't say anything hurtful. And then she started lecturing about reputation and how I've once again ruined it because I raised my voice.

Fast forward a few days she's been giving me silent treatment along with my dad while giving me snide comment all along. Now bear in mind I have apologized on the second day of silent treatment. She continued silent treatment and her snide comments until the day before yesterday I replied back to something she had said. I basically told her how me and my sisters felt (I'm the oldest of 4) without mentioning names and told her that if there was one thing she had passed on to us from her family was that we didn't want to become a mother like her, and how I honestly didn't miss her or minded not talking to her at all. My dad was present and he got defensive and said if I become even half of her I should thank god. However I do think my mum was hurt be what I said.

She asked me about why and all about my feelings but I didn't speak about them accept for the basics. She's tried that before when I was younger and I fully opened up to her 2-3 times before and regret it 100%, because she acted like she cared and then humiliated me immediately after. My mum got angry and I told her she was a good mum but basically there were things that really hurt us and I told her to stop the snide comments and acting like a child. And she told me she can act like a 5 year old or a cat if she wants to because she's my mum.
She then accepted defeat after speaking with my sisters who agreed with me and then said that maybe we should spend some time apart and rebuild our relationship. I agreed.

Not even 2 hours later I heard her screaming at my dad and venting about what we told her and how I basically accused her of abusing her and being a bad mum, although I did not use the words or anything similar and had multiple times told her that she had been a good mum when it came to the other departments.

She got angry with me afterwards again and I remained calm this time and just told her that she was proving everything I said earlier. She got triggered and stormed close to my face and said whether I was trying to trigger her and I told her if she was getting triggered it was her problem. She stormed off and came back a few minutes later and told me she felt sorry for me that I could treat my mum like that and she would never do that. (Backstory 2: she doesn't have a relationship with her mum or brother and her dad is dead. Her mum had her when she was 35 and didn't really pay attention to her and loved her younger brother instead. Her grandmother was more like a mum to her or so I was told. Her mum is now 72 with alzeimers and bucket load of other problems.)

Fast forward 2 days later, she's once again doing silent treatment with even more vile snide comments, and is trying to dirty my sister's minds about me. I feel very emotionally exhausted especially with my exams starting in 2 days.

To be honest my love is on its last straw and I can visibly see the disgust and dislike I have towards her in my eyes. I'm exhausted and now have to worry about whether she'll take me to my exams and how its going to affect my life from now on. I'm just really upset that she can treat me like that and my dad sees no wrong about her. Like I would never treat my child like that! I feel like bursting into tears and can't focus on anything! I'm worried its going to affect my exams and don't know how to broach the subject and apologize to my mum.