What do you do when your person dies?

Do you have that one person? You know, that person that you can call any time a day and tell anything? That person that would show up at your door if able in a heart beat if they are needed? That person that knows EVERY thing about you, or just knows, plain and simple?
I have a Facebook friend from high school that lost her person over a year ago. She made a post today about how much she misses this person. It made me think about the people in my life.
This has happened to my mom more than once. Her first best friend that I remember was Nita Bruce. She talked to Nita daily for hours on the phone. This was before cordless phones even existed! My mom and Nita would talk and talk and talk for HOURS every night before bed.
Nita got cancer when I was very young. She lived with it for years and years. She finally passes when I was 14 years old.
After her passing, I'm sure my mom felt  more than a loss. More than a whole in her heart. More than I can even imagine.
She lost my dad in May of 2014. They had been married for over 63 years.
Then, she made a friend named Juanita when she worked at Meijer. This friend also ended up living in the same apartment building as my mom. They talked a lot and visited. Juanita also helped check in on my mom's cat when mom would leave town or go to the hospital.
Earlier this year, her friend Juanita had a stroke in my mom's apartment. The paramedics came and got her. My mother read in the news paper a few days later that her friend had passed! No one came and told her!
Since her friend's passing, she has she has been very depressed. She has lost her person, again.
What do you do when you've lost your person? I have had a few instances in my life where I've had that person, but they didn't die. I can still check in on them on Facebook, or even call them. Sometimes, we gain or lose our person based on life experiences. We move off to college and lose that best friend from high school.
Maybe we learn that person we thought was our person wasn't so trust worthy in the first place.
We still feel a loss when that person isn't involved in our life anymore. There's a whole in our heart. Does that hole go away?
In my mom's case, she has always been faithful in knowing that she will see those lost in the afterlife. But what if you don't believe in the afterlife? How do you go on with your own life with the loss?
I know that people use the arts, meditation, nature, and other things to help fill their holes, but does the feeling of loss ever go completely?
No, I don't think so.
I've been dreaming a lot about my dad lately. He has been on my mind subconsciously. I haven't been thinking about him to much during waking hours, and my subconscious mind may just be worried I would forget about him. 
I'm not going to. I know that.
Currently, my person has had a ton of loss and health issues. I have debated whether or not I should drop everything and go to her. Does that make me a terrible person for her? She is only about two and a half hours away, yet, my life has been consumed with crazy business! I'm feeling like I should have dropped everything and gone to her months ago, yet, I haven't been able to. I feel anchored down by responsibilities that I have here. Should I feel this way?
I'm so happy to have my person here on this Earth. I hope she knows I love her.
Have you ever lost your person?