The CT will more than likely be to check the blood flow in your your carotid artery (sometimes they do a carotid doppler test instead).
The MRI will be to check for any abnormalities/signs of weirdness in your brain
The nerve tests will be Nerve Conduction Studies, designed to check that all your nerve pathways are working ok.
Has your GP referred you on to a consultant now in light of your diagnosis ?
What medication are you on ?
What you describe - the nausea/sickness and intolerence of light & noise are normal for classic migraine. The best thing you can do is lie down in a quiet, dark room and attempt to sleep it off.
I suffer migraines too and unfortunately pain-wise when I get one there is nothing I can do about it. Nothing works to take the edge off meds wise for me (I have tried everything, over the counter, GP prescribed, consultant prescribed, you name it). I am now on a drug for Topamax (Topiramate is the generic name) which is actually an anti-seizure drug used in epilpsy sufferers but they discovered that the brain and body behave very similarly during a migraine attack to how how they behave during a classic grand mal seizure, and so in lower dosages the drug has been found to reduce the frequency of attacks (and in some patients eradicate completely). It is a serious drug though awith serious side effects and it is one you simply cannot run the risk of getting pregnant on (high birth defect risk) but for me it has really helped my migraine symptoms which were very debilitating and incredibly frustrating.
Best of luck Fab.