Why do I get headaches after drinking coffee?

Caffeine dilates blood vessels and that could be the cause of your headaches. Some people get them when they drink coffee, eat chocolate, etc...some get them when they miss their coffee chocolate etc:) As for staying awake, I'm sure others will have good suggestions. Mine would be keep your blood sugar level by eating several small meals/snacks and trying to get in a bit of exercise to keep blood and hormones pumping.