Now, did you notice the 1st 5 letters of ETERNity spell ENTER if rearranged? That is because death is not an EXIT but an ENTRANCE into eternal life. The word eternity comes from the latin word for age. Theologians, like Augustine and Anselm who lived about a thousand years ago, see us as composed of who we were at all the different times of our lives... as in past + present + future. So, our eternal being will be the sum total of all that we have "become" rather than merely what our past has inscribed on us... our completed self.
As you can see, the heartache will dwindle to nothingness as you add up to all God has in store for you. Go ahead. Invest all of yourself in eternity. The investment will reap high dividends!