Headache

I had had a headache since the day before yesterday after my study presentation.
(Oh, "had had a headache..." is a little like a tongue twister, aha!)
I think that this headache was maybe caused by the fatigue of presentation and its preparation.
And it has been colder these days, especially since yesterday.

I must take care of myself not to catch a cold.
And I shall have much sleep.
All I need is a rest.