Hello and welcome, Celia. The one-thing-at-a-time approach will be just fine. Amber123 recently did the same thing.
The answer to this specific question is rooted in human evolution. At every stage in our development as a species there has been fierce competition for the resources necessary to survive. The survivors all the way along have been not just the strongest or the smartest, but those with the greatest will to live.
We didn't always have religion to drive us, you know. Before our ancestors even had the intelligence to conceive of gods or ponder the meaning of life, if they lacked a strong will to survive they would not have survived and we wouldn't be here. Those who were content not to survive or procreate were quickly scooped out of the gene pool by the dangers of the harsh ancient world. The survivors passed down their determination to us, as instinct.
On a personal intellectual level, I'm an atheist and I want to survive because I don't think I have any other life but this. There is a great deal of joy to be had, and to spread, and I want to make the most of it before I die.