What worries were often prevalent in Robert Louis Stevenson's life?

Three major worries for the somewhat melancholic Stevenson were health, his career path, and religion.
Robert Louis Stevenson's health was poor throughout his life. When he was an infant and a young child, he came close to death many times. His family had to hire a nanny to be with him full-time. As a school-aged child, he missed a lot of school because he was confined to bed.  
Stevenson made it to adulthood, but poor health continued to plague him from time to time. As young man, he lost a lot of weight, became depressed, and nearly had a nervous breakdown (more on that later). After Stevenson married, he and his family moved to the Pacific with the hope that the warmer climate would help his health. (He had tuberculosis, a wasting cough, which was not helped by the cold rainy climate in his native Scotland.)
Stevenson died of tuberculosis at age 44. Despite his poor health, he had lived a full life, had many adventures, and wrote prolifically.
Stevenson was a sensitive, intuitive type who seemed born to be a writer. This caused him some worries about the path he would take in life. He came from a family of engineers and lighthouse keepers, and it was expected he would follow in their footsteps. Stevenson could not make himself stay interested in engineering. To please his father (who was a loving parent but also put some pressure on Robert, his only child), Stevenson then earned a law degree. He had no enthusiasm for law either, and by his early twenties, he was writing full-time. His gift was so strong that it could not be restrained.
Finally, religion was a problem for the sensitive Stevenson. His loving parents were Calvinists, a sect of Christianity. Calvinism, with its emphasis on people's inherent sinfulness and inability to save themselves unless God changes their hearts, is considered by many to be a strict and gloomy form of Christianity. When Stevenson was a young man, he was forced into a confrontation with his parents in which he admitted he no longer believed in God. They were bitterly disappointed. The conversation resulted in a long-term strain on the relationship, and cast Stevenson into a depression. It was after this that he came near to having a nervous breakdown. He was saved by the support and listening ear of a few good friends. 
Although Stevenson officially rejected the God of his parents, his outlook on life remained shaped by what he had been taught. The Strange Case of Dr. Jekyll and Mr. Hyde, particularly, shows Stevenson knew well the deceitfulness of the human heart. It is a book that could have been written by a Calvinist. Dr. Jekyll's experience in the book also suggests Stevenson was familiar with dynamics of addiction.
http://robert-louis-stevenson.org/

https://thehumanist.com/magazine/september-october-2015/features/robert-louis-stevenson-says-no-to-religion