I can identify with this, Margaret. It's horrid, isn't it?
When I saw the specialist, he made a point of distinguishing between 'all the time' fatigue, and that crashing, sudden fatigue which comes and goes. The latter seems to be the greater indication of an estrogen problem (as opposed to a vitamin deficiency, kidney problem etc which will cause more continuous fatigue). I get it far less now than when I did before I was taking estrogen. It would literally come on with little warning and I would really struggle to keep my eyes open, regardless of where I was (which put me off driving). It would feel like there were leads on my eyes, weighing them down. Headaches and or nausea often came at the same time. Then within an hour I would be fine again.
I've now learnt that if it comes (luckily it's much rarer since taking HRT/the pill) I can't fight it. I close my eyes, force myself not to panic, and let it pass (obviously you can't do this if your'e at work or somewhere public!). I experimented with different foods in case it was blood sugar related, but estrogen is the only thing to have helped.
Damn hormones!
![Angry >:(](https://www.menopausematters.co.uk/forum/Smileys/extended/angry.gif)