I have quite severe headaches a few times a year (not booze related, migraine runs in the family).
When I have them most of the times I can't keep my stomach's content in.
Even to the point where I feel I have to throw up while my stomach is empty.
That lasts roughly half an hour, than my stomach settles down and I manage to lay down and catch some sleep.
I find it very unpleasant, but out of experience I know I feel faster when I throw up than when I don't.
Fortunately the few times I don't have stomach issues when I have headaches, I can throw up when I want to.