Not necessarily. Every religion have its opinion about the sense of life and death, and some believe in a life, or many lives after death, or none at all. In fact the religions are made only to reassure about death.
But for the Philosopher Epicurus, "death is nothing to us,for what is dissolved is deprived of sensitivity, and what is deprived of sensitivity is nothing to us". Therefore there is nothing to dread about death.
The first condition of happiness : reject the false opinions about Gods, get rid of the religion.
First it is one of the essential cause of the human misery, for the humans, convinced that their Gods interfer into their lives and have something to do in their success and their failures, their happiness and their misery, live in a constant state of fear of their Gods, in the anxiety to please or make them angry.
Second, it is impious : it is based on a false idea of piety, which itself is based on a false idea of God : first we dread him, we live in the fear and anxiety, then we are led, to please him, to commit crimes and injustices.
For Epicurus, "if God exists, it is uncorruptible (immortal) and happy by himself and, because of it, doesn't have to rule the world, nor has he anything to do with the humans and is a total stanger to them". "We live one time, and only one time, so as a matter of fact eternal life doesn't exist. So, you who is not the master of tomorrow, you differ to enjoy ! life dies by the delay and anyone of us dies busy".
So to answer your question, wheither you are an Atheist or a Christian, you are just the same human being, it is up to you to chose how you want to live and what sense you want to give to death, but that is just your opinion.
And yes, of course, there is spirituality without religion because there is freedom without religion.
Without freedom, there is no inner progress, nor happiness (which suppose a modification of oneself by oneself). But without freedom there is even no truth, for if someone is mistaken, his statement is the result of the necessity : he doesn't make a statement because he sees what is true, but because he can't do otherwise, not for reasons but causes. Such a mecanical truth is not the truth, for it can't be criticized or established by itself (the one who says the truth have no mean to know if it is true). Therefore, without freedom, there is no happiness, nor knowledge, nor research of one or the other.