Earlier this year ( 30th march) I lost my nana 
this is the first time I have lost a family member so close and this is my first time dealing with grief…not really sure how I am supposed to be or feel half the time so I usually go with the flow however now Christmas is creeping up on us I don’t know if I will cope…me and my brother were my Nana’s only grandchildren so being close didn’t even cut it she fought a battle with COPD until covid and pnuemoia took her life the heartache I have is unbearable
So sorry for the loss of your Nana. We always think they are going to be there forever don’t we.
It’s very early days for you, so what I would say is cut yourself so slack and be kind to yourself.
I have suffered the loss of several very close family members 
the most recent being my amazing husband and then his brother just two days later! Pneumonia took both of their lives but ironically it was covid pneumonia that took the life of my Brian 
There are no rules of how to grieve or how you are supposed to feel whilst grieving.
We are all different and we all cope or not with loss and grief in different ways.
I hope that you and your brother are able to support each other along this journey.
I’m sorry if this doesn’t help.
Please take care of yourself and when things get tough there will usually be someone on here that will be able to relate to how your are feeling x