There are some women who get a dip in their estrogen level mid cycle. I am definitely one of them.. I can tell when I'm ovulating ( or at least trying too) as I get 3-4 days of an upswing in my symptoms ( headache, palpitations, panic, flashes or whatever the symptom 'du jour' is), then am 'better' again until the week or so leading up to me period.
It's like a little dip in the estrogen peak...estrogen goes back up again briefly after ovulation in these women which is why you might feel better again for a few days before the estrogen drops of rapidly until period.
Good times...a double dose