What can i do to lessen my migraines?

Ive had migraines since i was in the third or fourth grade and i've gotten used to having them four or five times a week and being able to continue on with my day. I assume that they arent migraines that often but severe headaches...or maybe less severe migraines. Anyways, lately ive been getting the really bad ones where i honestly feel like could get absolutely no worse and just completely disables me...and over that past year ive been getting these bad ones more often than in the years before. Im headed off to college next month and i figure im going to be really stressed and not have time to deal with these migraines/headaches. ive gone to the doctor to see if there was some kind of trigger for me like stress or menstrual/horomone changes but there really is no pattern...i also kept a food log for months and there was still no pattern. Ive tried taking daily medication to prevent them but my body becomes immune to stuff extremely easily. I also have insomnia and ive read that irregular sleeping patterns contribute to migraines but ive also become immune to all the sleeping medicines ive tried, including kinds the doctor has prescribed. If you have any ideas or know some other trick i havent thought of i would very much appreciate it!!!