I just got back from being away from a month. Today I had a horrible horrible horrible migraine and its already 8pm and I have no food in my house.
Seriously now listen to me and I will cure your migraine.
First take 400 mg of ibuprofen.
Second start on 64 oz of water. Don't pound it, drink it slowly
Third get a wash cloth and soak it in rubbing alcohol. Put in high on the back of your neck near the base of your skull. If you have someone to gently rub the muscles in your neck do it, if not do it yourself.
This works 95% of the time for me.
You are most likely dehydrated from your travels causing your muscles to stiffen and giving you that severe headache.