Times change, Void.

In the old days, a woman who felt out of sorts, weary, or upset, could tell her gentleman, "I have a headache." The gentleman, being gentlemanly, would say sympathetic things and watch her retire. It was a fine code phrase; it could mean she was upset with something that had happened, or it could mean that she had a headache. It allowed her to maintain dignity before guests.
I have my own code phrase. I don't get headaches. I get tired. And like the headaches of yore, my weariness covers everything from hormones to exhaustion.
It can mean "I stayed up too late last night, worked hard all day, and now I feel like screaming because you just asked me to wash the dishes."
It can mean "I have been working and you've been sitting on the couch, but I don't want to say anything because I think you were working earlier when I wasn't around, and anyway, I don't want to seem petty."
And it can mean, "You're telling me of the grand trip you're going to take soon, while all I have to look forward to is work and church and hearing of the fun you're having, and I feel depressed and petty, and I should be grateful to have this job, and it's a wonderful job, but I don't--I really don't--want to be mature right now, I want to have my job and a wonderful six week vacation to travel wherever I want to in the world."
And it can mean "I'm just weary."

And all of these meanings will be covered by three words: "I'm just tired." So might the women of old have said, "I have a slight headache."