How do you fill the void left by a person? You can’t.
How do you make their pain go away?
You try to meet new people so they will come and replace them. So you don’t feel the pain anymore. But new people need to be able to create their own space or you will hurt them in trying to fit them in the wrong place.
That void can only be filled by that one person who is never coming back. But that is okay. You still have memories and lessons and funny stories and warm moments. They will fill that space. Not just yet though. I know those memories are painful right now but they will stay. Some weeks, months, years later you will tell the story of this person without feeling that pain and you will know that despite the final moments of bitterness, they did hold a special place. And they changed you and in many ways you will never be the same person again.