Chronic migraine patient here.
To treat migraine you need to do it ASAP. The goal is to stop it before it gets big. Obviously if you've never had one you'll not know when it's coming on.
I recommend you get a GP appointment this week or next week to get some medicines lined up in case you get another one. Migraines are often treatable and they dramatically affect your quality of life so it's worth popping a couple pills for.
I suggest you ask about:
Triptans: you can ask for oral sumatriptan which will take an hour or two to work properly. Or you can get injection sumatriptan which works within 10 minutes but is less commonly prescribed and you might not like injecting yourself. You could also ask about nasal Zolmitriptan spray which works within 15 minutes, but wears off faster than oral sumatriptan. Depending how long your migraine lasts (longer or shorter than 12 hours) you can pick if you'd rather Sumatriptan or Zolmitriptan.
Ask about an anti nausea pill. Some will treat dizziness as well. Stemetil works wonders for many people but they might not want to prescribe this as a first course of action. There are milder drugs available and you might as well try what the doctor suggests. Take it as soon as you notice migraine, preferably with the Triptan.
Triptans will not work if your migraine is established. They're taken on onset in an effort to stop migraine in it's tracks.
You can take up to 2 Triptans in 24hrs according to the package instructions
If you take it as instructed and you don't benefit completely (as in your migraine goes away) then you need to go back to GP to tell them this. I wish I had.
Without a script or doctor appointment, you stand a good chance of aborting a migraine with:
3x normal strength ibuprofen
Or
3x normal strength aspirn
Taken straight away as soon as you notice you're getting migraine.
Paracetamol might help with pain, but it doesn't abort migraine to the best of my knowledge
Try to avoid any opiates. The doctors may suggest cocodamol. I hear people ask for opiates but they're a nasty class of drug. I mean if that's what works for you, ok. But be careful.
See The Migraine Trust.org for information. I believe they suggest basically everything I've said here, but in much more thorough detail.
Seeing your normal GP is essential. It's usually a condition that responds well to treatment and there's a fair deal that can be done for the occasional migraine.
Read up on triggers. Hormones, smoke, fragrances, alcohol, dehydration, too much or too little sleep, repetitive noises, flashing lights, stress--- all are well known triggers. Frankly I don't know why food is so often cited as a trigger. I don't know anyone with a food trigger but lots of people with alcohol or perfume or noise triggers. For me it's often light and dehydration.