I've had a migraine that has lasted for 3 days. i've taken various otc medication and imitrex (sumatriptan) with no result. what else can i do?

You may have MOH: Sounds to me as if you may have crossed the threshold which many people do of medication overuse headaches (MOH). Stop taking all the OTC medications and quite possibly too many doses of Imitrex (sumatriptan) which you should take no more than twice in 24 hrs. and no more than 4 doses in 7 days. Start filling out a HEADACHE DIARY to take to a doctor who knows how to read and interpret the diary....but NIX OTC's

See your doctor: I presume that you have tried the usual resting in a dark quiet room. Since you have tried different medicines without improvement, it's time to see your doctor for further treatment.

Prolonged headache: With a headache lasting three days, you should be examined and treated by your physician who will determine the type of headache and,if necessary, order any appropriate tests including referral to a neurologist.

Not migraine ?: Not likely to be primary migraine if it has lasted 3 days. Sleep will usually abort a migraine.

Atypical Migraine: Although it would be very unusual for a migraine to last 3 days, it is not completely unheard of. If it is the 'worst headache of your life' I would proceed to an emergency department for additional evaluation and treatment options. Rest will usually relieve a migraine. If it persists or recurs I would go to see a neurologist for additional evaluation and care.