When a person can't find a deep sense of meaning, they distract themselves with pleasure. - Viktor Frankl

I doubt whether a doctor can answer this question in general terms. For the meaning of life differs from man to man, from day to day and from hour to hour. What matters, therefore, is not the meaning of life in general but rather the specific meaning of a person’s life at a given moment. To put the question in general terms would be comparable to the question posed to a chess champion: “Tell me, Master, what is the best move in the world?” There simply is no such thing as the best or even a good move apart from a particular situation in a game and the particular personality of one’s opponent. The same holds for human existence. One should not search for an abstract meaning of life. Everyone has his own specific vocation or mission in life to carry out a concrete assignment which demands fulfillment. Therein he cannot be replaced, nor can his life be repeated. Thus, everyone’s task is as unique as is his specific opportunity to implement it.

Don't aim at success - the more you aim at it and make it a target, the more you are going to miss it. For success, like happiness, cannot be pursued; it must ensue, and it only does so as the unintended side-effect of one's dedication to a cause greater than oneself or as the by-product of one's surrender to a person other than oneself. Happiness must happen, and the same holds for success: you have to let it happen by not caring about it.

"The incurable sufferer is given very little opportunity to be proud of his suffering and to consider it ennobling rather than degrading" so that "he is not only unhappy, but also ashamed of being unhappy."