What prescriptions did the ER give you?
What other medical conditions do you have and do you take any other medications?
Could be migraines, go to your gp and he may prescribe you with strong pain killers.
I had a 15 day migraine and was admitted to my hospitals neurology floor when I started having seizures. I was given DHE 45 intravenously to stop the migraine. It had awful side effects but man did it work wonders for the migraine. I was never told why I had a 15 day migraine but many causeas were ruled out.
If you have insurance contact a neurologist for an appointment and find out what they can do.
I now take Imitrex and Topomax to reduce the number of headaches and to stop thm once they have started.