Why?

I am tired right now, so if this turns out a bit emotional, please forgive me.
I am actually looking for a response to very long haunting thoughts. I am hoping for a "been-there" kind-of response, or, "I know someone who has been there."
Is it odd that I have been haunted the last two and a half years with thoughts of widowhood? Thoughts of what I would do... IF or WHEN? Sobbing because of it? Is it a lack of faith? Am I forever broken? Why am I grieving so much when he is still with me? He might even be cured or healed, and I am STILL stressed out and crying. Why is it so scary to believe? What should I believe? Will I still have to grieve if he does... you know? I mean, I have been doing that since we first suspected he had cancer... with a few breaks here and there. I am soooo nervous about the upcoming PET scan... if it returns... are there any options... proven options... this seems so long and drawn out, and I am starting to feel old.
Maybe I need a nap. Well, unfortunately, I didn't get one when the kids did, so the chances of getting one now, are nearly zip. Yawn!