Thanks to you both for replying - really appreciated. I seem to get it at the same time I get fatigue, oftemn around ovulation time or else before period. I can get weird burping too at the same time

When my GP tested my hormones he found my estrogen was low and suggested HRT which I have taken for a month. After three weeks, had three or four days of severe nausea and fatigue and couldn't decide if it was the normal thing and HRT not yet working, or because the HRT had clashed with my own cycle and made the oestrogen level too high. That's when I came across your posts. It's such a relief to know that I am not the only one who experiences this as it's not such a common symptom on here.
Again, so grateful for you for replying, B x