Again extream head pain, nausea, vomiting, dizzy sensitivity light&sound. Again er, test, treatment. Ct-clear pain med+zofran.=diag:migraine. Sent home!

Daily meds. It depends on how often this occurs, but it sounds like you may need to be on a daily medicine to prevent these headaches. You should also try to eliminate the common headache triggers if you haven't already tried that. And maintain a headache diary to try to identify any potential triggers. Good luck.
Migraine. Yes. Migraine could cause above symptoms. I advise you to consult a neurologist to get proper diagnosis and treatment.
Call your OB now! Unfortunately i don't know anything about you, but any pregnant woman reaching her mid-trimester with a severe headache needs to get a blood presssure checked and evaluates for pre-eclampsia which can be life threatening to you and your baby. People of advanced age are at higher risk. If you don't have pre-eclampsia, you may want a neuro evaluation for treatment with a triptan. Try caffeine.