"There are times when you work extremely hard and you don't get the benefits. Fret not"
The following is a tale that I had had as a lesson in school... The original tale is in Sanskrit, this might not be an exact copy.
There was a town, well known for its weavers. Every other house had a weaver, and they were very talented. They used to sell their wares in various other cities and they became prosperous over the years. But among them was one man who was not satisfied. This weaver was the best weaver in the entire village, so good that no other weaver came close to him in talent. The cloth he wove resembled pure gold in quality. However, he was never able to sell his wares for some reason or the other, and lived the life of an average man. He was unhappy because other weavers who were far inferior than him were far richer. He didn't understand the reason for this.
One day, his wife asked him to not lose hope and go to Puri to sell his wares. She said that she had heard that the patrons there were very generous when it came to rewarding quality cloth. She asked him to make the best quality cloth to sell there. And so he did. He made the best silk cloth, one so high in quality that it shone brightly. The lustre was remarkable. He went to Puri and sold all his wares within the first day. He had made an enormous amount of money and was very happy. On his way back, he had to pass through a jungle. The darkness, the wild animals and the fear of dacoits made him feel that spending the night on top of a tree would be a lot safer than venturing out in the forest.
As he slept, he had a dream, or maybe it was a vision. He saw two people standing and talking. And one asked the other, "Where did you get that money?" And the other replied "It belongs to that weaver. He is good at weaving, but his money belongs to me." They began walking away. The weaver awoke, startled. It was daytime. He quickly felt his money bag and found that it was empty. Bewildered, he started running around like a mad man, searching for the men in his dreams. But the forest was a deserted one. Only the trees and the birds around him seemed to be the lone living creatures around him.
Disappointed, he walked back home. His wife asked him how he was back so soon, and if he had made a lot of money. The weaver narrated his tale. She listened, patiently... Then she asked him not to worry, for God favours those who work hard. She asked him to work hard again, and make better quality material, to sell it and make a better profit, for she knew now that his efforts were getting rewarded. Sure, the money that disappeared was a strange event. But then she didn't like to see her husband so disappointed. And so, our hero began weaving once again and produced cloth far superior when compared to its predecessor.
Once again he made a fantastic sale, earned a lot of money, reached the forest and took the same decision of spending the night in a tree. He again saw a similar vision. And when he got up, the money was gone! This entire cycle repeated again, a third time. The weaver was disgusted, disappointed. He found that there was no way that he could get out of the rut... He decided to end it all.
And so, he made a noose out of the climbers, and was about to hang himself when suddenly the two men of his vision appeared in front of him, they were floating in the air. The first man said "Don't make this foolish move, oh noble weaver" The weaver looked at him, tears in his eyes "I see no reason to live. Why should I? No matter how much I earn, I lose it, or I am just not able to make money. What more can I do?"
The second man replied "My dear friend. This is fate! This is destiny... It is not every time that you get what you deserve. It is not every time that the harder you work, the more you reap. You need to accept life, accept what is given to you. I am not asking you to not put in effort, but when it doesn't pay, understand that that is not the end of the world. Go ahead and work hard. Maybe you have great fortunes awaiting you in the future." Having spake thus, the two men disappeared. The weaver sat, pondering for a while... And then walked home, with renewed zest.
The moral of the story is not to be gotten wrong - It doesn't tell you to not work hard. It says that there are times when you work extremely hard and you don't get the benefits. It could be as simple as studying hard for exams and not clearing, or trying to stabilise your relationship and failing, or trying to master a skill that your friend has. In the last case, if you have a friend who is an expert artist and has a knack, then no matter how hard you try, you may not be able to beat him. Talent and hard work are not the same. This reminds me of the character Rock Lee vs someone else like Sasuke from the anime Naruto. The latter is extremely talented and can master things quickly. The former becomes really good through hard work, never giving up. But he lacks the ability to do it in one go. He practises a lot over time and gains skill. But if Sasuke, the genius, works as hard as Rock Lee, the hard worker, Sasuke can easily go beyond Lee through sheer talent combined with hard work. Rock Lee should realise his limits.
Lots of people get depressed due to failure in exams and in love... Note, this was perhaps your fate or destiny. As Krishna said, "Karmanyevaadhikaaraste maa phaleshu kadaachanaa" which means work and don't worry about your fruit. If you must get it, you shall surely get it.