So sorry for the loss of you’re sister at 38.i totally understand what you’re fealing. I lost my only younger sister in April 2020 after a, sudden out the blue diagnosis of a brain tumour she died within 12 wees just over.
I too felt like the world had shifted. I can only describe it as my heart being ripped out stamped on popped back in and I’d to then try and go on.
It didn’t feel like it for me at the time and it won’t for you but it does get a little tiny bit easier as the months pass and you adapt to the new normal.