I know that it sounds hard sometimes. Trust in God. What must be done will be done, and for a reason.
This is so hard to take in and embrace sometimes. Whether it be love (Which I have just experienced.), death, or anything. The feeling of loss leaves us moments that sometimes we believe we're diminished to no more than an empty shell. Remember that even when you're feeling alone and scared, there is someone standing right beside you... waiting for you to raise your hands to the sky and unleash all that is withering inside of you, and surrender yourself to him.
Under God, "loss" is non-existant. He will wipe away the tears and offer solace unlike any other.
Let me assure you, that regardless of what happens, your grandfather will always be alive and with you. As is so often said, "Have faith." - Things will be OK when all is said and done.
Be strong. You are not alone. EVER.
You're in my prayers, sister.