The aim of this paper was to examine the relationship between mental health in the period before, during and after Valentine's Day in young people. The research was conducted through an online survey and was conducted in three waves, with 94 participants in the first wave, 34 in the second, and 29 in the third. The data collected in the survey included sociodemographic characteristics, mental health measured by the Short Mental Health Questionnaire, the level of life satisfaction measured by the Life Satisfaction Scale, depression, anxiety and stress measured by the DASS-21 questionnaire, a question about overall life satisfaction and self-created questions about Valentine's Day. The results showed that there is no statistically significant connection between mental health and the quality of the relationship in young people. Then there is no statistically significant association between the levels of negative mental health in young people regarding the period before, during and after Valentine's Day, where mental health was expected to be the best in the period before Valentine's Day, and the highest in the period during Valentine's Day. Furthermore, there is no statistically significant difference between the level of negative mental health among young people, nor differences in the degree of perceived quality of a romantic relationship with regard to the period before, during and after Valentine's Day. The results showed that mental health before Valentine's Day is worse than in the period during and after Valentine's Day, and that mental health in the period during and after Valentine's Day is of the same proportion in young people. The results also showed that the estimated quality of the relationship among young people is equal in all three periods, that is, before, during and after Valentine's Day. Rejected hypotheses point to the need for additional research, as well as raising awareness of potential mental health difficulties during the period of symbolic days of the year, namely Valentine's Day.