Imagine you don’t exist. Nothing of you exists. You are completely gone. You can’t feel anything, you can’t experience love, you can’t do anything, not even think. It would be said if there is nothing after death and you would be gone forever.
However the universe you live in exists. You exist right now just like the universe you live in exists. When you die, you are still part of this universe. The law of conversation of energy tells us that energy can not be destroyed nor created. If consciousness is just a form of energy you will live as long as the universe lives. No matter what happens to you, you would still be part of the universe, maybe in a different state. Maybe you would be a rock. Pretty dead, but to some extent you would still exist. Because you are part of this universe.
However the universe is going to die one day, just like us. For me the most likely result of the universe death is the evaporation of all subatomic particles as there is a less concentration of energy. You would disappear eventually. Or would you?
If string theory is correct, we live in a multiverse. Maybe there are many different multiverses out there. With different laws, some that might not even have string theory, but those do not exist in our perspective, since they do not react to our multiverse in any way. In their perspective we would also not exist. Existence is relative.
My point is. Even when this universe dies. You are still part of the multiverse. Therefore you still exist. When every particle in this evapoates, it might just be going to another universe.