There are no words big enough or meaningful enough for all you have gone through and are going through. I am so sorry for your losses.
A year ago I lost my best friend to agressive brain cancer and my dad four month later. That still doesn't compare and no one understand your grief the way you and God do.
You need to grieve, weep, and own your own feelings. Christians are so quick to try and push away any signs of mourning as if it is an affront to faith in God. That is so untrue. There are seasons in our life and yours is one of tragedy. When Jesus learned that his friend Lazerus had died he didn't jump up and down and say, "Hey guys, don't worry, I'm about to do something great, and I can't believe you are crying." Instead he wept. Well if he can weep and mourn, then that example is good enough for us. It would be inhuman and dishonest to pretend that any part of this doesn't hurt. God wants honest. For me I found that in Psalm 23 it says that God walks with us through the Valley of the Shadow of Death. It doesn't say he takes us out of it but he will walk with us as we cross. It also doesn't say, "So let's get comfy and enjoy being here. A few throw pillows and it will look like home!". It is not home, but we aren't alone. There are no words that will help, but know that you aren't alone.