There is definitely a correlation between migraines and sleeping habits for some people. I get migraines if I oversleep or dont get enough sleep or if my sleeping pattern changes (a lot of sleep one night and little sleep the next night). It sounds like with your job being the way it is, you don't have control over your sleep patterns.
Migraines also seem to have a cumulative effect for me where if I don't sleep enough and I'm really stressed all get one, but if I just don't sleep enough but everything else is in order, I may not get one. I've been trying to reduce the medication I take for migraines by pinpointing and eliminating my migraine triggers (I recommend reading the book Heal Your Headache, it tells you how you can do this).
I'm also started taking Magnesium and it seems to have really helped my headaches. Magnesium doeesn't help everyone, just about 50% of migraine sufferers.
I hope this helps!