Experiencing alternating periods of happiness and then depression, particularly in a cyclical pattern like the one you described (around two to 3 weeks of happiness followed by a week of depression), could be indicative of a mood disorder rather than just ordinary mood swings. This pattern might be suggestive of a specific type of mood disorder, such as bipolar disorder or cyclothymic disorder.
Bipolar Disorder: Bipolar disorder is characterized by alternating periods of depression and mania or hypomania. In Bipolar II disorder, individuals experience depressive episodes similar to major depression, but their "ups" are characterized by hypomania, which is less severe than full-blown mania. This pattern might resemble what you described, with longer periods of happiness and shorter periods of depression.
Cyclothymic Disorder: Cyclothymic disorder is a milder form of bipolar disorder, where individuals experience periods of hypomania and mild depression that are less severe but longer-lasting than typical mood swings.
It's important to remember that self-diagnosis can be inaccurate, and only a qualified mental health professional can provide an accurate diagnosis. If you have been noticing this pattern and it is affecting your daily life, relationships, or work, it's crucial to seek help from a mental health professional for a proper evaluation.
It's worth noting that other factors could contribute to these mood fluctuations, such as stress, lifestyle changes, hormonal fluctuations, or situational factors. However, if there is a consistent and significant pattern of alternating mood states, it's best to seek professional assessment.
Keep in mind that seeking help is a positive step towards understanding and managing your emotions better. Mental health professionals can provide appropriate support, therapy, or medication if needed to help stabilize mood fluctuations and improve overall well-being.