My mood collapses before every period. Is that a real thing?

Yes, and it has a name. Mood, irritability and anxiety that arrive in the one or two weeks before a period and lift within a few days of it starting are premenstrual, and when they are severe enough to damage work or relationships the pattern is called premenstrual dysphoric disorder. It is recognised, and it is treatable.

What distinguishes it from depression running underneath is the clearing: a symptom-free stretch after the period. Keeping a simple daily note across two or three cycles is what makes the diagnosis possible, and it is the single most useful thing to take to an appointment.

Treatment options include approaches to the cycle itself and approaches to the mood, and which is offered depends on what else you want from a method and on your history.

The pattern can change over time and often intensifies in the years before menopause, which sometimes surprises women who had managed it for decades.

This cannot tell you whether your pattern fits, whether something else is contributing, or which treatment would suit you. A diary over two cycles will tell a clinician more than any description written afterwards.

• Here is two cycles of notes — does this pattern fit?
• What are the treatment options, and what is each one aimed at?
• Could anything else be adding to this?
• How long before we would know whether something is working?

Seek help today for thoughts of harming yourself at any point in the cycle. A symptom that comes and goes with a cycle is still an emergency when it is that.