I am so sorry that you have to miss your darling boy 
Life is so fucking unfair.
I am a bereaved parent too, my son and my daughter both died many years ago.
I remember the very early days all too well, it's just all consuming as you come to terms with your new 'normal'.
This week, and up until your darling boys funeral, you may find yourself feeling sort of OK. Obviously sad, but please do prepare yourself. Right now you're still doing things for your son, throwing yourself into arranging his funeral. I found after their funerals much harder because that was all my jobs done for them at that point. I dont mean to be insensitive, but I really do wish that someone had warned me that I would feel that way.
Right now you're in a massive dark fog, its everywhere and you can't see any way out, over time, and there is no set time, the fog does lift, you wont notice it happening as the process is so slow, and you mustn't rush yourself to feel 'better' either. I'm not saying it goes away completely, but one day you will look back and notice that the fog you're in now is a dark cloud in your sky, and you'll know that you have found your way to cope.
You may find yourself, I know I did, almost feeling guilty because other people are sad, and find yourself comforting them. You need to remember that you and your DD are the important ones here, people should be looking after you, not the other way around.
This path, unfortunately, lasts a lifetime, there are many of us walking it, all at our own pace, and sometimes, even years later, we slow down or drop, but the people who understand are the people who have been through this, and there are many of us on here, always ready to listen, even if it is you just saying the same things over and over again. Dont ever be afraid to post here for support.
Right now just take things a minute at a time, just keep looking to the next minute and getting through, soon you can look 5 minutes ahead, then 10, then an hour until you can start looking at some semblance of a future, again, it's a slow process, and dont let anyone rush you. People are very keen for you to seem better because it makes them feel better, but this is 100% about you and your DD.
Also prepare yourself because people can be really fucking stupid and say all sorts of shit, people love a cliche, or try to say deep and meaningful shit, or even just try to avoid you. I'm 21 and 13 years into this bereaved parent life and I think (hope) I've heard it all now, but some of the drivel spouted in the early days still shocks me now.
Most of all be kind to yourself, and dont be afraid to be selfish and do what you need to do to get through as best you can.
Once again I'm so sorry that you have to miss your beautiful boy