Where were the headaches located exactly?
Did you feel eye pain at the same time?
Are you a migraine sufferer?
Do you find your night sleep refreshing?

It's possible you could be suffering from "ice pick headaches." To MandMs point, they're associated with migraines... they last from 5-30 seconds and feel like intense, stabbing pains in your head. Usually they're not accompanied by any other symptoms, but fatigue might make sense given how painful they are.

My boyfriend (a migraine sufferer) started getting ice pick headaches recently and they totally freaked him out. Since we've been able to stop his migraines with decongestant allergy meds, we tried that and it worked. He'd had the headaches on and off for two days, but since the allergy pill, he hasn't had any.

If you want to try it, remember to get an allergy medication with pseudoephedrine in it (e.g. Claritin-D or the Target pseudoephedrine brand). Don't get the one off the shelf... ask the pharmacist (you might have to show your ID).

Good luck!