So sorry to hear your news OP.
Not normally one for posting things like this. Lost my dad last October to sudden cardiac arrest outside his house. He was 73 I was with him whilst they tried to bring him back, and followed the ambulance to the hospital. I still feel numb so many things I didn’t have chance to say. Not a day goes by without me thinking about him or wishing I could share some news with him.
I just try to take each day as it comes, remember the happy things the little things. It’s the hardest thing I have ever had to deal with. As said you just think your parents will always be there.
Keep going allow yourself to grieve and that will allow you to heal.
Rich.