We need some basic information before it's possible to make any assumptions about what is going on.

Basically a history of you and headaches: how long?; see a doctor (and a headache specialist?); what meds, if any, are you using & dose/frequency? Have you been diagnosed as having Cluster?

Broadly speaking, variability is a major characteristic of Cluster.

Good question to compare notes from others. 

Some report they get slammed like a freight train at the beginning of their cycles and others it gradually increases, then peaks, then tapers off.  Everybody is unique!

Personally, my cycles pain intensity levels are typically very predictable as follows:

Beginning weeks....frequency minimal, pain level minimal to moderate.

Middle of cycle....frequency moderate, pain level moderate to intense.

End of cycle....frequency high, pain level intense.

My cycles are generally 8 to 12 weeks.  I have suffered 32 years as an annual episodic CH sufferer with rare remissions longer than 1 year. 

Might consider documenting a personal diary of each cycle so you may compare your notes to future cycles. 

A few things to document may include dates of cycle, times of day/night you get attacked, duration of attack, frequency, pain levels, triggers, preventative meds, abortive meds, diet, exercise, stress levels, weather, lifestyle changes, etc.

A diary helps conclude info specific to YOU, such as what I am able to share about my pain intensity levels. 

Good Luck!

I usually get what I call the Grande Finale toward the end of my 6 mnth long cycles. Doesn't mean it's over just that I'm past the worst of it. This can be a week or more of pure CH hell, for me.

Others have said this happens to them too.

Don

I get the grand finally as well, about 2 weeks of pure hell and a trip or 2 to the ER. Then I know that the beast is packing his bags and will be gone in a couple of weeks. My cycles usually last 4 to 5 months with 1 to 5 year remissions. I have had CH for over 35 years and I can tell you, for me anyway, that the pain at the end of my cycle has gotten worse as I get older but the remmisions get longer. In remmision now 7 months.
Bud