Hiya, I was reading a post asking about coffee. I agree with comments there that it's important to listen to your body.
I have put my reply as a post in case it is useful to have it all in one place.
Over the years I have developed a way of keeping down the caffeine while enjoying a morning brew.
This is tried and true, and the only way I can drink my morning coffee and feel a bit better than when I woke up, not worse (no AF symptoms).
This is the method:
First, coffee. The darker the roast, the less caffeine it contains. That's why the darker roasts are "after dinner". Lucky for us, these are the most flavoursome.
Next, the brewing of it. Anything that brews fast keeps down the caffeine content.
So, your or your local coffee shop's espresso machine, or your own little stove-top espresso pot. These push the heated water through fast under pressure, so there are two benefits to this: firstly, less time for caffeine to infuse into your brew, and secondly, the grounds are not sitting in the water (so not stewing caffeine into your brew).
Then, what you have it with. The object now is to keep the remaining caffeine from being absorbed quickly.
The more fat you have with it (good fat), the slower the caffeine will absorb into your system, which also keeps the effects milder. I use full cream milk. If you don't want that, then eat something not too 'skinny' with it. (Macaroons anyone? I think I have just proved by this that cake is a health food! Hah! Of course I have my coffee with breakfast so cake is unnecessary except as a medical emergency).
Comparison with other methods:
After years with this little system, I tried using a cafetière (French Press to our American friends), and in a fit of nostalgia for student days, a pour-over Melitta-type filter system. There was a difference. These methods caused some suspicious heart rumbles. So I returned to my old friend the Espresso pot.
With my little system, I can drink the equivalent of 3 espressos at breakfast without any discernible adverse effects. However, I have no coffee in the day, unless it's a rare treat out with friends - and cake.
And now to tea!
There is a trick a Home Help taught me which significantly reduces the diuretic effects of tea.
I am assuming it also reduces the caffeine (no the diuretic effect of tea is not due to caffeine).
The method is simple. Pour the boiling water on the tea, let it brew 2 minutes, pour it away. Pour new water on, brew as normal.
The thing is, with a decent everyday tea, you can't tell the difference in taste.
You could try it!