Hey there,
I know you're in a lot of pain right now and it feels as if your world has turned upside down. Losing someone you love is not easy, in fact it's really difficult. Right now you probably feel lost, sad, broken, and maybe even completely and absolutely exhausted, but one day all of that will go away. I can't promise you it will be soon because then I would be lying. You'll have your days in the future where it hurts and you'll cry, but you will be OK again one day. That I can promise.
There are many different types of heartbreak, but nothing quite breaks your heart like losing a loved one. It's an awful kind of pain, and it leaves you feeling empty. For you, the world stops, but you look around you and everyone seems to be doing just fine and you don't understand why they can't feel your pain. You may feel like you can't break down and cry or that you can't talk about how you feel, but you can and you should. Grieving is a part of life and it's something we all have to do in our own ways. Eventually you'll start to wake up in the morning and feel a bit better day by day. It's not going to be easy, but time will pass and your world will start turning again and things will get better.
The worst thing you could do in a time like this is destroy yourself or lose who you are in the middle of all your grief. I get that the pain is overwhelming, but if you're going to change, change for the better. Be a better person and honor the person you lost by becoming the best person you can be, because that's what they want. Crying and screaming and being angry is fine for a little while, but that is not what they would want from you for the rest of your life.
We lose a piece of ourselves when we lose someone we love, because by loving them we gave them a piece of us. While you may be missing a piece of you, they left a piece of them in every person they loved and in everyone whose lives they touched. No, they may not be physically here, but if you just look around at the people who are hurting just as much as you, you will see the person you lost in everyone of them.
You've got a long road ahead of you, but you are not alone. In most cases you are not the only one who is affected by this death, so sit around, tell stories, look at pictures, sing, laugh, and cry. Time does heal, but nothing will heal you more than being around the people who understand what you're going through and who you're missing. Yeah, there will be days that just plain suck, but there will be days in which you know you are doing right by the person you lost and that they would be proud.
Just remember they live in you and in the people around you. No one is ever truly gone until every single person they touched is gone. Keep their memory alive and pass on the love they gave you. You're going to hurt, but in the end you just have to persevere.