Maybe on your Chinese birthday, you were trying to follow a particular Chinese astrological belief related to your birth year. For example, if it was your year of the Rat and you were supposed to do certain things to bring good luck. But things went wrong and instead of good luck, you had a series of small misfortunes that day. It made you feel like the Chinese traditions that you were relying on didn't work for you, and that can be a very sad realization.
Your sad story might be that on your Chinese birthday, you couldn't find any place that served the special Chinese birthday food you were craving. It can be really disappointing when you're looking forward to something like that.
I'm not sure exactly what your sad story is regarding your Chinese birthday. Maybe it could be that you were far away from your family on that day and couldn't celebrate it with them in the traditional Chinese way, like having a big family dinner with all your favorite Chinese dishes.
Once there was a young girl in China. On her birthday, her parents had promised to be home early to celebrate with her. But they both got caught up in their work. She waited all day long, with a cake she made by herself. As the night fell, she blew out the candles alone, feeling so sad and lonely.
Well, one sad birthday I had in China was when I was expecting my friends to come over. But they all forgot about it. I had prepared a lot of food and decorated my place nicely. I sat there all alone, looking at the cake I had bought for everyone. It was really disheartening.
Once on my birthday in China, I got sick. I had a high fever and couldn't do any of the things I had planned. I was supposed to go out and explore a new part of the city. Instead, I was stuck in bed all day, feeling miserable. It was a really sad birthday because I had been looking forward to that day for a long time.
A Chinese student who was studying abroad really wanted to go back home for his birthday. But he couldn't afford the flight ticket. On his birthday, he watched videos of his family back in China celebrating birthdays in the past, and he was very sad as he missed his home and family so much.
Maybe there's a sad story behind a happy birthday because of unfulfilled expectations. A person might have hoped for a big celebration with all their friends, but due to some circumstances like friends being too busy or having a fight, it turns out to be a lonely birthday, which is sad in the midst of what should be a happy day.
A woman's birthday was on a day when she found out she had a serious illness. She had been so excited for the day, planning to go out with friends. But when she got the diagnosis, all the joy of the birthday vanished. She sat in the doctor's office, crying on her birthday, thinking about the uncertain future.
Financial problems can also lead to a sad birthday story. Maybe a family couldn't afford to give their child a proper birthday celebration. The child would see other kids having great birthdays and feel left out and sad. For instance, a poor family where the parents couldn't even buy a small cake for their daughter's birthday.
One time, for my wife's birthday, I planned a surprise picnic. I found a beautiful spot by a lake, filled a basket with her favorite foods like cheese, crackers and fresh fruits. I also got her a beautiful necklace. When she arrived at the spot, she was so amazed and happy. It was a simple yet memorable birthday for her.
One good source could be Archive of Our Own (AO3). Just search for 'X Reader sad birthday' on it and you'll find a variety of works. Some might involve a character forgetting the reader's birthday, leading to a sad and angsty scenario.