I felt so sad reading your story. My partner was not a JW, but was raised in a very religious home. A home that made god and armageddon a priority. Ironically, they got involved with a few different cults and cult like people. One couple who, as it happens, turned out to be ex JW's who saw the methodology and thought they'd control people themselves. They were very good at it.
Of course when he met me, I was studying my way into a cult and came from an alcoholic home...we had a lot in common.
Anyway, my point is. He grew up feeling that the end was always near. He was always preparing for the worst. Every news report, any email or letter received from his parents would be enough to put him on high alert. The cupboards would be stocked and adrenilin would flow.
He is a recovering alcoholic. And has been sober for the last 3 years. I am convinced that aside from the hereditary factors of the disease, living in constant dread played a huge part in his alcoholism. He himself has said, just as you have, whats the point? I'm not going to be here long, and he is probably doomed anyway. I was with him when the drinking became out of control...and the suicide feelings emerged....and those drunken days of 'happiness'....they weren't real. He got to the point where he couldn't even convince himself that drinking solved his problems.
He has since been in recovery, found fellowship and support in AA meetings and discovered that he does have a future and is now planning ahead and planning on growing old with me instead of drinking himself into oblivion.
I can't stress enough what a benefit councelling, AA and other supports networks are. Finding one that suits, where you feel you fit in is vital. AA is non judgemental and you would be surprised how much you connect with others on a personal level. Even if they have different backgrounds. You will hear your story coming from the mouth of others and leave every meeting in awe. Unable to comprehend that other people can and do feel exactly the same way as you.
For what its worth...that nagging voice is the hardest thing to get rid of. My partner no longer believes that armageddon is on it's way. But I still see an inkling of despair when he has contact with his parents or receives and email about end times. Old habbits are hard to break. But at least they don't dominate his every waking hour any more. They are manageable. There is hope, you can get through this. And you can do it with help. The only thing you have to do is go get it. You have made a start by sharing your thoughts here...that is commendable. But there is nothing like being in a room full of people who understand and share your emotions with you. And there is nothing like a councellor that seems to read your thoughts and pushes you to be the person they know you can be.
My heart goes out to you...I understand your struggle.