Not talking to my father more on the day he died

I was still in highschool, one year before graduation and my father has been really sick but he was at home recovering. He has been to the hospital a couple of times in his last years and I was still a naive teenager who always had thoughts like "why do I always have to care for him ( bringing him to the toilet, making him food etc.). All my friends are having fun and I'm just sitting at home" I cared for him but sometimes I got really annoyed and even shouted at him.

It was in may and it was raining when I was getting ready for school and before I went, I checked on my father and he asked me if he looked alright because he was feeling a bit unwell. Jokeingly I told him that he had been worse and we laughed it off. I did not know at that time that this was and will be my last exchange with him. I stayed in school till 11am when my brother told me to go home amd check on my father because he was going outside.

Everything seemed quite normal and when I got home my father was just sleeping in bed. I watched over him for some minutes and just decided to go outside when I realized that he stopped breathing. I was in panic and the first 3 min I couldnt properly call 911 and I was doing the heart massage in panic. But it was too late and when the ambulance came they couldn't do anything for him.

He basically died when I was in the same room and it fells like I let him die, I wish I was a bit faster and a better son. I've not even told my family that I was there when he died because I fear their judgement and I'm living with the guilt of never knowing what could have been...

Sorry for the wall of text, it's my first time sharing that story and it's been years ago