I have had migraine since childhood. Cigarette smoke triggered them then, and library searching when wearing contact lenses when I was at university, but that apart there is connection between migraine and triggers.
Since the menopause, as others say, the pain is far less, mine have also become very random. Until the menopause, I would have the same kind of migraine, ocular, severe but not to often for decades at a time, but since the menopause ocular migraine has returned, vestibular migraine, extreme nausea, you mention it, I have had it.
I was woken from sleep one night last week with the familiar one sided pain. No triggers, took my usual medication and it had gone by evening. heven't had a migraine like for about 20 years.