I made my dad cried, I feel so bad. What should I do?

It all started with me being really hot tempered and recently I tried to change. Whenever, someone raise their voice at me I will have to raise my voice even if that person is my parent. Well like I said earlier, I have been trying to change myself recently, me growing older (just turned 18) makes me want to correct my shitty personality. And for a beginner, this is really stressing me out. I have like 100 things I would like to talk back about but I promised myself to stay quiet. At the moment I'm also in my exam periods (which stress me out even more) and I just screwed up 2 of my 5 mock exam papers.
I don't really get along well with my relatives, you could say I don't love them.
Just on the day that I screwed up a mock paper, my aunt texted me saying happy birthday, so I said thank you and the conversation carried on until she mentioned "study hard and become a doctor" and I told her that "yes I will study hard but I already changed my mind, I am no longer planning on doing medicine", normal people would ask why you change your mind? or so what are you planning to do now? but she said "PLEASEEEE BE A DOCTOR, I wanna see you as a doctor" I was shocked and didn't know how to reply to her politely that THIS IS MY LIFE, I MAKE MY OWN DECISIONS, so I told her "sorry but it's already too late, I already dropped biology" she said " it's never too late, just take it back" I was pretty pissed off by this time already and said "nope, the exams are in june, theres not enough time to prepare for it" so she said "your father won't encourage you to be a doctor, I know him very well" so I said "he doesn't want me to be and I don't want to be, when I was young I kept on mentioning that I want to be a doctor and my dad will always ask me if I am sure. Well I guess he knows how hard it is to do something he doesn't like since he was forced into doing medicine" she said "he shouldn't say that, isn't it because he is a doctor that he met your mother? Ask him" I said "No he didn't say that he was forced into it, I deduced it myself, we all know that he is into maths and physics, so why else would he do medicine? and also whatever job you do, you have the chance of meeting your soul mate, if he wasn't a doctor then he might have met my mother in a different way" and she just needs to pissed me off even more by saying "Hahaha, I don't think so, since your mother is also from medical field" so I said "you don't have to meet your soul mate at work place, if two people are meant to be, even if they are living at 2 opposite ends of the world then they will meet! but these things happened in the past and we can't go back and change it so there's no point arguing" and i guessed she sensed that I was pretty pissed off and said "I'm telling you in general" so I tried to calm down and said "thank you very much for your concern but whatever happens it's fine with me, after all this is the decision I choose to make, so I will live with it" and she said "Yes you have to" I WAS LIKE WTF WTF WTF?!?!?!?!?! I KNOW I HAVE TO, YOU DON'T HAVE TO POINT IT OUT STUPID, so I broke down and cried so much. Every year she will text me saying happy birthday and everytime she does that my father and I always manage to get into a fight about her. I cried because I was so angry that she was about to make my father and I fight again. As soon as I see my father, he asked how's your exam? I heard your aunty said happy birthday to you" I didn't want to cry in front of my father, so I said "I don't want to talk about it" and there were silence, after that I wasn't sure what happened but everything went blank and all I remembered was that I was crying really hard yelling at my dad about how much I hate my aunty and him asking why am I crying, why are I so weak, why am I making it too easy for people to control my emotions and said just to ignore my aunty. I remembered yelling at him to stop talking about it. Afterward, I went up to my room to calm down then we sat down and talk. The thing is my aunty's dream was to become a doctor but her grades are too poor, so she tried to push her dreams on to me. Apparently it also happened to my brother but at that time my brother and I didn't have a phone or anything she could contact him through, so she could only pressured him through my dad. She asked my dad why he doesn't push my brother and I to become a doctor and he said "I do push my children to decide what they want to do and whatever they decide I will support them" I originally love my dad more than anything but at this point I love him even more. So afterwards both of us made up and I said I was sorry, I have been stressed for quite awhile now... I didn't manage to finish my sentence and he just hugged me and cried. He said "please understand me, I just want you to be a strong person..." I don't remember what he said much but I remembered saying "I understand, I'm sorry, sorry, sorry, sorry..." and then we let go of each other, we both said good night in tears and part. After that happened it made me wonder about all the things I have done in the past, like I said I fight with my dad everytime my aunty is mentioned and I am also not on a very good terms with relatives on his side, so we always fight about that as well. How much did it kill him inside everytime I said I hate my relatives? I am so angry at myself, my father is such a nice and kind man and I return his favor by being an asshole? I couldn't stop crying for hours. I know that I already apologize to him and he is a very understanding person, he really knows that I'm guilty of it and forgave me..... but I feel.... horrible. What should I do?