It's not easy. Even that very sentence sounds like such a gross understatement, I can feel it churning my stomach. But I will tell you right now, you're going to keep breathing. Even when it feels like you can't, or maybe that you aren't anymore, you will. This is not long term "advice" of any sort if such a broad thing even exists. This is simply some words from me to you, if you should need it at all, on how I survive the moments that seem impossible to get through, and what I hope can help you too.
When the reality of their absence sets in, the minutes pass like months and it can seem like nothing is real. Good. Don't let it be. I know that sounds like the opposite of what some may say is "healthy" coping, but I'm telling you right now that if you can't take it anymore, don't. I mean it. You're going to lose your mind if you don't allow it to just shut off sometimes. Watch a movie, watch TV, anything. You don't have to distract yourself with company or conversation, sometimes the more mind-numbing the better. Law and Order saved my life. It still does. Any time I can feel the overwhelmed anxiety setting in, I can put on Law and Order and just stare at it and it takes me somewhere else. Find a show or movie that you can direct focus on instead and stick to it. It's presence as even a background noise at times can become key to ever being able to pull yourself away from the edge of being consumed.
Everything is different. There is no true escaping that, there is no real pretending. The underlying scream in your mind of this truth won't soon leave you, but creating rituals of calm or subtle things can help establish some ways to combat it. Become a creature of habit. I'm not saying start smoking, though honestly I'd rather you inhale smoke sometimes if it can make you remember to breathe. What I mean is, find small things, anything, that can become a simple comfort. I get those packs of tiny donuts that cost 75 cents at the gas station. Just mindlessly getting those before school in the morning often gives me something "normal" to do on days that it feels like torture to just have to go to school in the first place and be involved in a world that doesn't seem to understand how wrong it is now. Let small things fall into a pattern that can create a sense of normal for you. It's these things that will be there to turn to when the panic does set in.
Sleep. Please. Please get some sleep. And don't sleep alone if you can't, don't make yourself. Have your little sister come sleep in your room, stay with friends, ask your partner to make sure you fall asleep first if they can. You need it. This is another place where TV could come in handy, just make sure you sleep. For months I slept on the couch outside my mom's bedroom. Just because I needed to be closer to her. Because I knew she felt my pain too and it was too hard to wake up beside anybody else for a long time, but I didn't want to be alone. Don't make yourself be alone. Get some sleep.
I can't tell you that you're going to learn something profound from this. I can't tell you that tomorrow or two minutes from now you will be ok. But I promise you that you are meant to still be here. No matter how it feels right now, there is a reason you are still breathing and so you have to keep breathing. You miss them. That's an understatement, every single attempt to try to sum up how this feels is going to be an understatement, except one... You love them. And you are loved back. Still. These moments will prove in a profound way that even the gap of death can't undo that: it can't undo this love. Love still. Speak of them often. Boxing up their smile, shutting out their voice... these things won't always protect you the way you are trying for. Love them still. Above all else, don't try to let go of that.
Remind yourself that you have to keep breathing. Breathe.
Don't forget you are loved. Don't forget how important that feeling is. Don't forget that the pain of loss stems from the depth of love.