I have lost my belief in the eternal blissful afterlife. So I no longer think that I will live that life which is the only life to me that brings me joy and meaning. This is what has driven me to a rage.
Think about this.....
What you believe has changed, but the truth of the matter has not changed.
You once believed you would live forever -but you were apparently not certain, because something changed your mind.
Now you believe you will not live forever, but you should not be certain of that.
Only your beliefs have changed -you have not actually gained proof or even enough supporting evidence.
Consider what made you change your mind. Should it have made you change your mind? Sometimes when one thing is seen to be untrue, we falsely believe something else is untrue -when one really does not depend on the other.
Sometimes when we are disappointed or disillusioned, it means we need to understand things better.
It may be that you found something else to be not as you once believed, and it brought all of your beliefs into question -so think about what changed your mind.
You may be focusing on the wrong issue.
It would be best to realize that whether you live forever or not, what is right and what you should do is still the same.
Also realize that you are not certain you will not live forever, and that If you do, it will be by God's decision, so live in a way that is good and creates happiness.
Do not think of your own happiness. Love others and you will be happy.
It might help to consider the issue of eternal life on its own.
If you were only a biological process, you would not be considering such things.
You also have spiritual processes. You have a spiritual desire to survive just as you have a physical desire to survive.
We think about eternal life for a reason. We have hope for a reason.
There is a reason we live just long enough to gain basic experience.
Notice that other life forms do not have such concerns. They do not consider such things because they are not destined for the same future.
Everything about us and our situation points to the potential for, and likelihood of, eternal life. However, we cannot give ourselves eternal life.
If, therefore, the decision is not ours, then we should consider the one with the power to make that decision -and live as citizens of a perfect world and universe.
As written, If you wish to enter into life, keep the commandments.
Even if you did not live forever, everyone keeping the commandments would make the world a wonderful place...
.......but.....
None of us can be perfect the first time around -and that is why we have a temporary existence at first. Every last human mistake will be undone -those who are willing to do right will be resurrected to life, and others will be resurrected to judgment -which is toward making them willing to do right.
I'd suggest actually reading the bible. Few actually know what it says. Listening to many religious people just gets confusing.