Also just let those tears fall and get those feelings out and for the feelings tell them to your mom and she may even open up to you which would help her too. Also it may be painful to talk about but it helps I still miss him(grandpa) but so does his son (my dad) and his wife(my grandma) but that's because we love him so much.
Just remember... tomorrow is another day. Another day of life a day of love a day of surprises. And your sister wants you to live to see it. Don't beat yourself up about it; give yourself time to let out your feelings. But know that taking your life won't make anything easier for your mom. She's just as broken as you, and she needs you. Please, don't ever hesitate to talk to us... we're all a PM away. You can get through this, I know you can. heart