The COVID-19 pandemic has a significant impact on human life. This study aims to assess the prevalence of depressive and anxiety symptoms, and the assessment of the quality of life in different stages of the COVID-19 pandemic based on an online nationwide survey. The study was based on a voluntary, anonymous, and authors' own questionnaire. The first section assesses sociodemographic status. Then, standardized psychometric tools were used such as the Beck Depression Inventory (BDI), the Generalized Anxiety Disorder Assessment (GAD-7), and the Manchester Short Assessment of Quality of Life (MANSA). The study was conducted in three stages corresponding to the waves of the COVID-19 pandemic in Poland. The survey involved 5,790 respondents; 2,457, 1,626, and 1,707 for the first, second, and third pandemic wave, respectively. It was found that anxiety and depressive symptoms increased as the pandemic progressed. There was no significant effect on the subjective quality-of-life assessment. Moreover, there was a gradual decrease in anxiety about being infected with COVID-19 as well as reduced adherence to the Minister of Health's recommendations. As the COVID-19 pandemic progressed, depressive and anxiety symptoms increased among Poles. Women, singles, and people with prior psychiatric treatment are more likely to develop the aforementioned symptoms.